Michael Seibel
Born 1982 · Age 43
Entrepreneur, co-founder of Justin.tv/Twitch and Socialcam; longtime Y Combinator partner and former CEO of the YC Startup Accelerator; investor and board member (Reddit, Dropbox).
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Life & Career Timeline
Family moved to East Brunswick, New Jersey
Seibel moved with his family from Brooklyn to East Brunswick as a pre-teen (lived in Brooklyn his first nine years).
Graduated East Brunswick High School
Completed high school at East Brunswick High School (class of 2000).
Matriculated at Yale University (approx.)
Began undergraduate studies at Yale University, majoring in political science (graduated 2005).
Graduated Yale University (BA, Political Science)
Received a bachelor's degree in political science from Yale University; became friends with Justin Kan while at Yale.
Finance Director for Kweisi Mfume's U.S. Senate Campaign
Served as finance director for Kweisi Mfume's unsuccessful U.S. Senate campaign in Maryland.
Moved to the San Francisco Bay Area
Relocated to Silicon Valley / Bay Area after working on the Senate campaign and to pursue startups.
Co-founded Justin.tv
Joined Justin Kan, Emmett Shear, and Kyle Vogt to start Justin.tv (originally a lifecasting experiment), founding team of four.
Justin.tv pivoted to an open live-broadcasting platform
In fall 2007 Justin.tv expanded from a single lifecast to a platform allowing anyone to broadcast live video.
Became CEO of Justin.tv
Seibel took on the CEO role at Justin.tv; served as CEO from 2007 through 2011.
Raised early funding for Justin.tv (investors named)
Justin.tv raised venture funding from investors including Alsop Louie Partners and Tim Draper (exact round amounts not specified in sources).
Justin.tv lifecasting launched
The original Justin.tv lifecasting stream (Justin Kan's life) launched publicly and garnered attention.
Mentored Airbnb and recommended them to Y Combinator
Acted as an early mentor to Airbnb founders and recommended the company to Y Combinator.
Justin.tv reached profitability (company milestone)
By 2010 Justin.tv had become profitable, per accounts of the company's history.
Stepped down as CEO of Justin.tv to focus on Socialcam
Seibel left day-to-day leadership of Justin.tv (CEO tenure ended 2011) to build Socialcam.
Co-founded and launched Socialcam (mobile video app)
Seibel co-founded Socialcam, a mobile social video app; launch noted in March 2011.
Socialcam joined Y Combinator (Winter 2012 batch)
Socialcam participated in Y Combinator's Winter 2012 batch, accelerating growth and exposure.
Socialcam downloads surge (13M+ in 3 months)
Socialcam reportedly added over 13 million iOS and Android downloads in about three months during rapid growth.
Socialcam acquired by Autodesk (~$60M)
Autodesk acquired Socialcam after roughly 18 months of operation; transaction reported at $60 million.
Joined Y Combinator as a part-time partner
Seibel began advising startups at Y Combinator in a part-time capacity, mentoring hundreds of founders.
Named first African-American partner at Y Combinator
In October 2014 YC announced Seibel as its first African-American partner, increasing diversity recruiting efforts.
Listed as co-founder of Justin.tv/Twitch on personal site
Personal site recounts co-founding Justin.tv and the eventual sale of Twitch to Amazon.
Twitch acquired by Amazon (~$970M)
Twitch (the gaming-focused spinout from Justin.tv) was sold to Amazon for reported ~$970 million.
Justin.tv re-focused and Justin.tv service shut down
Justin.tv operations were shut down to allow the company to focus on Twitch; transition completed in 2014.
Appointed CEO of the Y Combinator Startup Accelerator
Seibel became CEO (Managing Director) running YC's core accelerator program and leading early-stage efforts.
Published advice and essays on startups (ongoing)
Began publishing a large body of written advice for founders (many essays collected on his site and YC blog).
YC-related media appearances and public speaking
Regularly appeared in media and gave talks (e.g., Wired coverage, conferences) as YC leader and mentor.
Published 'YC Has Changed' essay
Posted essay discussing how YC evolved over 13 years (Sept 28, 2018).
Published 'The AM/PM Debate - or How not to be an idiot CE O'
Published an essay reflecting on leadership lessons and CEO behavior (Nov 19, 2019).
Named to Reddit board replacing Alexis Ohanian
On June 10, 2020, Reddit named Seibel to its board; he replaced Alexis Ohanian and was called Reddit's first Black board member.
Accepted recognition for YC as incubation leader (TiE Global mention)
Referenced accepting TiE Global best incubator/accelerator award in 2020 while discussing YC's diversity goals.
Named to Dropbox board of directors
Dropbox announced Michael Seibel as a new board member on December 15, 2020.
Launched 'Life, Work, and Startups' podcast with brother Jason Seibel
Started a short podcast series with his brother discussing entrepreneurship (2021).
Maintains personal websites (CooksLarder, JonathansApps)
Runs two hobby/personal websites: CooksLarder.com (recipes) and JonathansApps.com (kids' apps).
Listed numerous personal investments (ongoing)
Personal seed/angel investments include Cruise, Brex, Figma, Rippling, Reddit, Clipboard Health, Promise and many others.
Fireside chat at Stanford (appearance)
Appeared for a fireside chat hosted by Stanford (event date listed as Nov 27, 2023 in references).
YC impact metrics (cumulative snapshot)
YC page notes companies Seibel has worked with are worth a combined $192B; he has done 6,500 office hours with 1,745+ companies and participated in 3,100+ interviews (cumulative figures as of page snapshot).
Public profile summary updated (personal site)
Personal site summarizes roles: Partner Emeritus at YC, board member at Reddit and Dropbox, co-founder/CEO history and family details.
Stepped down from YC leadership role; returned to partner
Announced on March 15, 2024 he was stepping down from his leadership role at Y Combinator and returning to being a partner after ~8 years in leadership.
Subject of retrospective founder profile pieces
Articles and founder profiles (e.g., founder stories) published recounting career arc from politics to Twitch, Socialcam and YC influence.
Key Achievement Ages
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