Today is the day pregnant Marissa Mayer starts her first day as the new CEO of Yahoo, after a 13-year long career at rival Google. As widely reported, she was one of the first 20 people to join Google when it was started in the late nineties.

But what happened to the rest of them (via this Quora thread), and other notable former Googlers, we wondered? Turns out 7 of them are still at Google.

The first 20

(not necessarily in that order)

1) Larry Page > Google Sergey Brin > Google Susan Wojcicki > Google Urs Hölzle > Google Salar Kamangar > Google Omid Kordestani > Google Joan Braddi > Google Marissa Mayer > Yahoo Craig Silverstein > Khan Academy Georges Harik > Chris Skarakis > Harry Cheung > Angel investor (Qwiki, Badgeville, etc.)
13) Steve Schimmel > Entrepreneurial advisor and angel investor (Roozt etc.)
14) Heather J. Cairns > Angel investor in women-led companies
15) Amit Patel > Red Blob Games Ray Sidney > Big George Ventures Kendra DiGirolamo > Driscoll’s Larry Schwimmer > unclear
19) Jim Reese > unclear
20) Gerald Aigner > unclear

Other notable ex-Googlers (aka Xooglers)

– Top US salesman Tim Armstrong left to become CEO of AOL.

Sheryl Sandberg was previously VP of Global Online Sales and Operations at Google and is now COO and board member at Facebook.

Paul Buchheit left Google to start FriendFeed, sold it to Facebook and later left the social networking giant to become a partner at Y Combinator

Bret Taylor, who was the CEO of FriendFeed but previously co-created Google Maps and the Google Maps API, is now the (outgoing) CTO of Facebook.

Aydin Senkut joined Google in 1999 as its first product manager, and now runs a venture capital firm called Felicis Ventures.

– Twitter was co-founded by two former Googlers, Biz Stone and Evan Williams.

– Foursquare co-founder and chief executive officer Dennis Crowley worked at Google after its acquisition of Dodgeball.

– DoubleClick founder David Rosenblatt, Google’s former President of Global Display Advertising, now runs and Group Commerce.

Chris Sacca was the Head of Special Initiatives at Google but went on to run an investment firm called Lowercase Capital.

Pinterest founder Ben Silbermann briefly worked at Google as a product designer.

– Instagram co-founder and now Facebook-er Kevin Systrom worked at Google for 2 years.

– Longtime Google sales exec Jeff Levick left for AOL but is now at Spotify.

Scott Hassan, best known as the founder of eGroups (bought by Yahoo) but also one of the key software architects of Google in its early days, founded robotics firm Willow Garage.

– Google Apps VP Dave Girouard quit to startup Upstart.

Jonathan Wall and Marc Freed-Finnegan, who played crucial roles in building Google Wallet, left this year to work on startup Tappmo.

Jason Liebman co-founded and runs Howcast after playing an integral role in growing strategic content licensing and monetization relationships for the YouTube, Google Video and AdSense teams for 4 years.

– James Whittaker, formerly Engingeering Director at Google, is now a ‘Web futurist’ at Microsoft.

Anyone else you think should really be on this list? The comment floor is yours.

And now for a blast from the past: here’s a video of Google’s weekly all-staff meeting, TGIF, recorded in December 1999.