Oh, it's somewhat arbitrary, but Facebook was founded in 2004 and by 2010 no longer counts to me as a "startup". I suppose 2010 is still pre-IPO (2012) and therefore has a chance for advantageous stock grants.

(Not lost in all this: over the years the tax treatment of option grants has changed! It used to be a hugely advantageous way of giving employees something of value, and that's been eroded a lot.)