Dan Siroker

Siroker worked as a product manager at GoogleGoogleGoogle is an American technology company founded by Larry Page and Sergey Brin and incorporated in 1998. It became an Alphabet subsidiary in 2015. Its businesses include internet search, advertising, software platforms, cloud computing, and artificial intelligence.Open the full entry on Chrome and AdWords, and then served as director of analytics for Barack Obama’s 2008 presidential campaign, using data to help the campaign make decisions.⁠[1][2]

In December 2007 Siroker’s team tested 24 combinations of 4 buttons and 6 media items on the campaign’s splash page with 310,382 visitors; the best combination had an 11.6% sign-up rate against 8.26% for the original page. Writing in 2010, he estimated that if the improvement held for the whole campaign it amounted to about 2.88 million more email sign-ups, 288,000 volunteers and $60 million in donations.⁠[2]

In 2009 Siroker and fellow Googler Pete Koomen founded Optimizely in San Francisco, letting users test and roll out website changes without altering a site’s underlying code. Optimizely completed Y Combinator in winter 2010 and was profitable by 2011, with clients including Starbucks and Disney. Siroker wrote in 2010, “We created Optimizely because we wanted to make experiments like this one easier to do.”⁠[1][3][2][4]

In 2012 Siroker returned to the Obama campaign, where his work helped raise the conversion rate of the president’s donation page by 50 percent. In September 2013 Optimizely raised a $28 million Series A led by Benchmark, bringing total funding to more than $31 million; it had 75 employees at the time, and its revenue grew 400 percent from March 2012 to March 2013. Siroker said, “Our success in 2012 really put us on the map.”⁠[1]

In September 2013 Siroker gave the talk “If Data Can Help Win Elections, What Can It Help You Do For Your Business?” at the Business of Software conference.⁠[3]

On May 20, 2014, a16zAndreessen HorowitzAndreessen Horowitz (a16z) is a venture capital firm founded in 2009 by Marc Andreessen and Ben Horowitz. It invests from the seed stage through the growth stage and provides operational support to its portfolio companies.Open the full entry released the podcast episode “a16z Podcast: The Next Wave of Internet Tools,” in which Optimizely co-founder Siroker spoke with Andreessen Horowitz general partner Scott Weiss and partner Tom Rikert about how the democratization of software development lets people without engineering degrees do work once left to developers, using Optimizely as an example of enterprise software born from the internet and discussing the next wave of internet tools. Titled “a16z Podcast | Bending Every Pixel to Your Will -- Optimizely and the Next Wave of Internet Tools,” the episode was uploaded to the a16z YouTubeYouTubeYouTube is Google’s video-sharing and creator platform, founded in 2005 by Steve Chen, Chad Hurley, and Jawed Karim and acquired by Google in 2006. Built around video uploading, viewing, and creator earnings, the platform has developed Shorts, YouTube Music, Premium, YouTube TV, and products for children, and is headquartered in San Bruno, California, United States.Open the full entry channel on January 1, 2019.⁠[5][6]

On August 20, 2015, a16z released the podcast episode “a16z Podcast: Tech's Biggest Ideas and How They Take Hold,” a conversation between Marc AndreessenMarc AndreessenMarc Andreessen is an American entrepreneur and venture capitalist, a co-founder and general partner of the venture capital firm Andreessen Horowitz (a16z). While in college he helped develop the graphical web browser Mosaic, then co-founded Netscape and Loudcloud (later renamed Opsware), and has long served as a director of Meta; he has also published essays such as “Why Software Is Eating the World.”Open the full entry and then Optimizely CEO Siroker at Optimizely’s annual Opticon conference. They discussed how Google, eBayeBayeBay Inc. is an online marketplace company headquartered in San Jose, California, United States, founded in 1995 by Pierre Omidyar; it started out with person-to-person online auctions and listed on Nasdaq in 1998. As of the end of 2025, it had 135 million active buyers, and its platform’s gross merchandise volume in 2025 was nearly $80 billion.Open the full entry and the web itself first looked like small point products, as well as optimization tools, privacy trends, artificial intelligence, virtual reality, bitcoin and robotics. The episode was uploaded to the a16z YouTube channel on January 1, 2019.⁠[7][8]

Optimizely was later acquired by the content management company Episerver. Siroker went on to co-found Rewind with Brett Bejcek; its desktop software recorded activity on a user’s computer into a searchable record. The company was later renamed Limitless and pivoted to AI devices, launching the $99 Limitless pendant, which clips onto clothing or is worn as a necklace and records conversations. It raised more than $33 million from investors including a16z, First Round CapitalFirst Round CapitalVenture capital firm.Open the full entry and NEA.⁠[4][9]

On December 5, 2025, Limitless announced that it had been acquired by Meta, with its team joining the wearables organization within Meta’s Reality Labs; the price was not disclosed. Limitless stopped selling the pendant that day, kept supporting existing customers through 2026 and began winding down the Rewind software. In his signed announcement Siroker wrote, “We're no longer working on a weird fringe idea.” Meta said, “We're excited that Limitless will be joining Meta to help accelerate our work to build AI-enabled wearables.”⁠[9][10]