In 2006 a U.S. physician who wanted a second opinion on a drug or a hard case asked nearby colleagues, went to conferences or read journals. Most doctors worked in small outpatient practices, away from the grand rounds, hallway consults and physicians' lounges where that talk used to happen SR47. Warnings about drugs could take years to reach them: Vioxx was on the U.S. market from 1999 until Merck withdrew it in 2004 over heart-attack and stroke risk, and one FDA analyst estimated it may have caused 88,000 to 139,000 heart attacks SR41. Investors who wanted clinicians' views paid expert networks such as Gerson Lehrman Group, which had sold them one-to-one expert calls since 1999 SR42. No place gathered what doctors across the country were saying, either for other doctors or for the people who wanted to hear it.
Sermo
Sermo gave U.S. doctors an anonymous room for occasional talk and sold what they said there to investors and drug makers, while Doximity gave them verified names and tools they used every day, so Sermo's U.S. growth stalled and it became a paid survey panel.
Why Sermo lost to Doximity
- 1 · 2006–07Anonymous handles over a license checkMembers were checked against license records but posted under handles; about 90% stayed anonymous (2016).How to win
- 2 · 2007–16A forum for hard cases, visited occasionallyHalf of 2007 activity was informal consults; by 2016 members wrote about one comment each a year.User-Generated Content
- 3 · 2010–14U.S. membership stalled near 130,000Growth slowed to about 4% a year by 2012; Doximity passed it with 250,000 physicians by early 2014.
- 4 · 2007–12Sold the doctors' conversation to hedge funds, then pharmaFunds paid $100,000–500,000 a year to watch; Wall Street budgets went in 2008–09; sold to a survey firm in 2012.Data Licensing
- 5 · 2012–25Rebuilt as a paid survey panelWorldOne moved its panel onto Sermo (2013); 700,000 surveys a year by 2016; about $150M revenue when offered for sale (2025).
Versus Doximity: Doximity gave doctors a verified name and free tools they used every day, then sold hospitals and drug makers reach to those named profiles SRX6 DXX-3. Sermo gave doctors an anonymous room they visited occasionally and sold what they said there SR48 SR3.
Arena: Market Conditions Before Sermo
How each step happened
Step 1 of 5 · 2006–07
Anonymous handles over a license check
Candour first
Sermo came from a doctor's worry about drug safety. Daniel Palestrant, a surgeon, set it up after the Vioxx recall as a place where physicians could report side effects and discuss cases with doctors across the country SR48. It opened in September 2006, free, without advertising and only for U.S. physicians SR37. At registration members were matched against databases of licensed physicians, but on the site they could post under handles and leave their profiles blank SR9 SR16. By October 2007 about 2,000 doctors were joining each week SR9.
The choice bought candour. A doctor could say what they thought of a drug, a case gone wrong or the state of medicine without putting their name to it. Peter Kirk, chief executive from 2012, defended handles as what set Sermo apart: "We allow doctors to create usernames and be anonymous on the network so that they feel safe to provide their real opinions," he said in 2016, when about 90% of members did so SR25 SR48. The cost was that the network held no professional identity. A colleague could not look up a named specialist on it, and later a recruiter or a marketer could not define an audience from it SR16. The check itself was thin: in 2007 a blog showed non-physicians how to register, and Sermo had to re-verify members SR6.
Rivals Doximity launched in 2011 with real names verified against DEA registration numbers and profiles pre-filled from public records SRX4 SRX1. Jeff Tangney, its chief executive, called real names and authentication "the biggest difference" between the two networks SR16.
Step 2 of 5 · 2007–16
A forum for hard cases, visited occasionally
Sermo's product was the conversation its members wrote. Doctors posted cases, voted on posts and could earn bonuses for contributions judged valuable SR5. In September 2007 about half of the activity was informal consultations among roughly 26,000 users SR46. Many came to vent about the profession SR52.
That need came up when a hard case or a grievance did, not every working day. Sermo did not carry patient work: its network was not HIPAA-compliant, the U.S. patient-privacy standard, so members had to avoid identifying patients SR23. A 2010 redesign and iConsult, an iPhone app for asking colleagues about a case, made the forum easier to use, but not part of the daily routine SR14 SR20. By its own count, its 550,000 members worldwide wrote 626,000 comments in the year to April 2016, about one each SR48.
Rivals Doximity began with HIPAA-compliant messaging and added free fax; by early 2014 about 25% of its members regularly used secure messaging, including eFax, and members sent more than 20,000 messages to each other a day SRX4 SRX6 SRX15. Medscape Physician Connect, part of WebMD, opened a competing physician forum in 2008 SR47.
Step 3 of 5 · 2010–14
U.S. membership stalled near 130,000
With members hidden from each other, each new doctor added posts but not a person others could look up, message or refer a patient to. Sermo had 115,000 physicians by mid-2010 SR14. By July 2012 it had 130,000, about a fifth of U.S. prescribing physicians, and membership had grown only about 4% a year for three years SR20. Sermo's marketing head drew the line himself in 2012: "We are not a network. We are a community," Jon Michaeli said, calling a network "very transactional" SR16.
Doctors who tried both saw the difference. A Sermo member who also used Doximity wrote in 2012 that on Sermo "physicians may be anonymous and that removes some of the ability to judge information presented in the forum" SR16. By March 2014 Sermo reported more than 200,000 U.S. physicians, a count that included WorldOne's research panel moved onto the platform the year before; Doximity had more than 250,000 SR23 SR22. Sermo now grew by adding panels, not by colleagues pulling each other in.
Rivals Doximity's Tangney said in 2014 that adoption tipped by sub-market, "a hospital, a city, or a specialty", once doctors felt left out if they were not on it SRX6. Its members included 40% of U.S. doctors that year and 70% by February 2017 DXX-7 DXX-6.
Step 4 of 5 · 2007–12
Sold the doctors' conversation to hedge funds, then pharma
How Sermo paid its way was set in its first year, alongside the forum, and it shaped the rest. Palestrant described the model in 2007 as "almost an arbitrage between our physician community and our clients": doctors paid nothing and saw no ads, while clients watched anonymized trends form in real time through a separate product and put questions to members SR3. The first clients were financial-services firms and government, paying roughly $100,000 to $500,000 a year SR9 SR5. In 2008 Bloomberg carried Sermo's feeds, surveys and panels to about 250,000 terminal users SR10.
Investors valued the talk as a trading signal, so revenue rested on the forum's volume and candour while members got nothing from it for their own work. When the 2008 crash cut Wall Street budgets, Sermo moved its sales to drug and device makers in December 2009, amid reported layoffs of over a third of staff SR13. Pfizer, its first drug-maker partner, could place content in discussions from October 2007 SR7 SR9; critics said that made the forum "the equivalent of a drug rep", and the ethicist Arthur Caplan called it "a kind of a one-way mirror" SR8 SR47. By 2013 clients could also buy "awareness campaigns" meant to influence what doctors thought of specific drugs SR44. Palestrant left in early 2012, and in July investors who had put in more than $40 million sold Sermo to WorldOne, a physician market-research firm SR15 SR19.
Rivals Doximity charged third parties for doctors who were named and opted in: an expert network paid it $200 per expert match, and by early 2014 more than 200 hospitals and health systems paid for recruiting, bringing its first cash-flow-positive month SR16 SRX6. Gerson Lehrman Group sold investors one-to-one calls with physicians SR42.
Step 5 of 5 · 2012–25
Rebuilt as a paid survey panel
WorldOne bought what Sermo could supply reliably: verified doctors willing to answer questions. It moved its own U.S. panel onto the platform in 2013, opened the network in 30 countries by 2016 and launched RealTime, a tool for fast, repeated surveys SR22 SR28 SR27. By 2016 Sermo ran about 700,000 surveys a year, paid members more than $16 million for surveys and counted 15 of the top 20 U.S. drug makers as clients SR48. Members now knew when they were working for a client, and were paid for it.
It also fixed what Sermo was: a research supplier competing with other panels and expert networks, not a place doctors went for daily work. Its verified panel of over a million health professionals took years to build, but established panels hold similar assets SR29 SR34. Abry Partners recapitalized the company in 2019, and it bought two research firms in 2023 to reach payers and oncologists SR29 SR31. In July 2025 Abry hired JPMorgan to sell a business with about $150 million of revenue SR33. The anonymous handles of step 1 had left Sermo nothing to sell but what members said or answered, and answering became the business.
Rivals Doximity kept doctors' daily attention and sold hiring and marketing against their verified profiles; its members included more than 85% of U.S. physicians, and revenue was $644.9 million in the fiscal year to March 2026 DXX-3 SRX11. Sermo does not appear among the competitors in Doximity's filings, which name WebMD's Medscape and OpenEvidence SRX14 DXX-3.
Key dates
- 2006-09Opens to U.S. physicians, free and ad-free
- 2007-06Palestrant describes an arbitrage between doctors and clients SR3
- 2007-09$25M round led by Legg Mason
- 2007-1035,000 physicians Adding nearly 2,000 a week SR9
- 2007-10Pfizer joins as first drug-maker partner
- 2008-10Feeds and surveys sold on Bloomberg terminals
- 2009AMA partnership lapses
- 2009-12Sales shift from Wall Street to pharma
- 2010-07115,000 physicians U.S. members; 1 million comments to date SR14
- 2011-11Doximity reaches 30,000 physicians under real names SRX1
- 2012-01Founder departs
- 2012-07130,000 physicians U.S. members, growing about 4% a year; WorldOne buys Sermo SR20
- 2013-09200,000 members WorldOne's U.S. panel moved onto Sermo SR22
- 2014-03Doximity passes Sermo with 250,000 physicians SR23
- 2016-04About 90% post under usernames; 700,000 surveys a year SR48
- 2016-05Nearly 600,000 members Physicians in 30 countries; RealTime surveys launch SR28 SR27
- 2019-02800,000 members Abry Partners recapitalizes; members in 150 countries SR29
- 2025-07About $150M revenue Abry hires JPMorgan to sell Sermo SR33
- 2025-10Self-serve advertising to verified members SR35
Sources
Oldest first.
- SR2 Sermo, online physician community, raises $9.5M, grows quickly. Reporting
- SR3 PHYSICIANS/HEALTH2.0: Sermo AMA interview. Founder interview
- SR4 Sermo Snares $25 Million. Reporting
- SR5 Sermo links doctors to one another -- and to investors. Reporting
- SR46 Sermo: All Cashed Up and Ready to Grow. Reporting
- SR6 Sermo Strikes Back: A Physicians' Online Community Lashes Out Against Bloggers Who Publicize Security Gap. Reporting
- SR7 Pfizer Engages with Nation's Physicians Through Sermo to Improve Patient Care. Company announcement
- SR8 Doctors let drug maker in on their talks. Reporting
- SR9 Pfizer Goes Digital with Sermo Partnership. Reporting
- SR10 Sermo-Bloomberg deal opens physician pipeline to investors. Reporting
- SR12 Sermo and AMA break ties, trade insults. Reporting
- SR47 How Big Pharma Listens in on Doctor Networks. Reporting
- SR45 Sermo, Inc. (HBS Case 809-142). Outside analysis
- SR11 Sermo, AMA spar over physician frustrations. Reporting
- SR13 Sermo Changes Strategy to Gain More Pharma Business, CEO Declines to Discuss Layoff Talk. Reporting
- SR14 All-new Sermo brings major enhancements to nation's largest online physician community. Company announcement
- SRX1 With 30K Doctors Now On Board, Doximity Is Fast Becoming The LinkedIn For Physicians. Reporting
- SR15 Par8o, from Sermo Founders, Aims to be Patient-Physician Matchmakers. Reporting
- SR50 Sermo co-founders leaves 'baby' for new venture @par8o. Reporting
- SR16 Sermo vs. Doximity: Can they co-exist in fight to build physician-only networks?. Reporting
- SRX2 Doximity: Professional network for physicians (transcript). Founder interview
- SR17 Sermo Taps Revolution Health Veteran Tim Davenport as CEO. Reporting
- SR18 WorldOne Acquires Sermo. Company announcement
- SR19 Sermo acquired by WorldOne. Reporting
- SR20 Market research - social media mashup: WorldOne acquires Sermo. Outside analysis
- SR37 From Community to Commodity: The Ethics of Pharma-Funded Social Networking Sites for Physicians. Outside analysis
- SR44 From Community to Commodity: The Ethics of Pharma-Funded Social Networking Sites for Physicians (Experts@Minnesota record). Outside analysis
- SRX3 Social media and doctors: Q&A with Doximity CEO Jeff Tangney. Founder interview
- SR21 WorldOne Secures $35M commitment from Deerfield Management. Company announcement
- SR22 WorldOne and Sermo complete U.S. integration, paves way for global expansion. Company announcement
- SR25 Peter Kirk: Sermo vs. Doximity = 'Facebook' vs. 'LinkedIn' for Docs. Founder interview
- SRX5 Doximity's social network for doctors now has more members than the American Medical Association. Reporting
- SR23 Social networks for physicians now trending #DoctorsLounge. Reporting
- SRX6 With 40% of U.S. doctors signed on, Doximity's Jeff Tangney reveals how the social network for M.D.s hit the tipping point. Founder interview
- SRX4 Doximity: Social Networking For Doctors. Reporting
- SRX15 Doximity Raises Another $54M to Pursue LinkedIn's Business Model Too. Reporting
- SR24 Big Changes to Come as Sermo and WorldOne Unify. Founder interview
- SR38 Getting to Pareto Optimality from Sermo - The Dan Palestrant interview. Founder interview
- SR26 SERMO, Top US Social Network for Doctors, Announces Global Expansion: Starts with the UK. Company announcement
- DXX-7 Doximity: Financing a Social Network for Physicians. Business school case (abstract)
- SR48 What is SERMO... and can we trust it?. Reporting
- SR27 Sermo launches new agile market research tool for health care professionals: Sermo RealTime. Company announcement
- SR28 Sermo Expands Global Network to Include 30 Countries. Company announcement
- DXX-6 Doximity Reaches 70 Percent of All U.S. Doctors. Company press release
- SR30 Sermo receives investment from private equity firm Abry Partners. Reporting
- SR29 Sermo Announces Significant Investment from Abry Partners. Company announcement
- SRX7 Doximity, Inc. Form S-1 Registration Statement. SEC filing
- SRX8 Doximity, Inc. Final Prospectus (424B4). SEC filing
- SRX9 Doximity more than doubles in NYSE debut. Reporting
- SRX13 Doximity, Inc. Final Prospectus (424B4) - competition sentences. SEC filing
- SRX10 Doximity CEO ignored Silicon Valley wisdom and built a $10 billion health-tech company. Founder interview
- SR31 Sermo Healthcare Community Expands Payer & Oncologist Reach. Company announcement
- SR49 Survey Finds 57% of U.S. Physicians Have Changed Their Perception of a Medication as a Result of Info on Social Media. Company announcement
- SR32 Scoop: Abry preps physician social network Sermo for sale. Reporting
- SR33 Abry Preps Physician Social Network Sermo for Sale. Reporting
- SR34 Sermo for Business. Current offer
- SR35 Sermo launches Engagement Manager, enabling on-demand advertising access to global community of 1M+ triple-verified healthcare providers. Company announcement
- SRX12 Doximity (DOCS US). Investor analysis
- DXX-3 Form 10-K for fiscal year ended March 31, 2026. Filing
- SRX11 Doximity Announces Fourth Quarter and Fiscal Year 2026 Financial Results. Company announcement
- SR1 Sermo. Reference work
- SR36 Sermo vs. Doximity: Comparing Physician Social Networks. Current offer
- SR39 Sermo (Acquired) company profile. Reporting
- SR40 Sermo - Abry Partners. Investor record
- SR41 Rofecoxib. Reference work
- SR42 Gerson Lehrman Group. Reference work
- SR51 About | Sermo for Business. Current offer
- SR53 Sermo 2026 Company Profile. Reporting
- SRX14 EDGAR full-text search: "Sermo" in Doximity filings (CIK 0001516513). SEC filing
- SR43 Daniel Palestrant, MD - Biography. Company-supplied biography
- SR52 What's your doc thinking? Web site offers clues. Reporting