A toast to its early code-cramming all-night product building sessions, Facebook  held its 31st Hackathon at its Menlow Park HQ starting last night--one last hurrah before "FB" starts trading on NASDAQ this morning.
Later today, Mark Zuckerberg  will remotely ring the NASDAQ bell at start of trading, post-hackathon, from Facebook HQ.
A packed crowd gave Zuckerberg a standing ovation.
Timeline, chat, and video features on Facebook today started off as hacks during the hackathons Facebook holds every few months.
Facebook will sell  421 million shares at $38 per share.
[Image: Brian Zeitler, Everett Katigbak, Matt Harnack, Francis Luu, Facebook ]
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