Does anyone know why "8" seems to be such an important number at Facebook (f8, Building 8, and I believe way back when they were using Fedora 8 the first time they stated their server operating system, though that is probably coincidental)?
Because in Slovenian you pronounce 8 almost the same way as "awesome" in English ;) (true, but not the reason)
This is a guess but only thing I could think of 8 is a lucky number in Chinese culture and Zuckerberg is married to Priscilla Chan who has Chinese heritage.
I read it was something like their hackathons started at 8 PM.
An existential reminder that bowing to Facebook is our eventual "fate/F8"?
Facebook has 8 letters?
I'm fairly sure this is the primary reason, just like a11y is shorthand for accessibility and i18n is short for internationalization. It also helps that F8 looks like "FB" and sounds like "fate" but those were likely just bonuses.