I remember someone doing some kind of calculation at some point trying to assess the cost of Reddit's hosting, and it being all the money in the world, but now that they're public we don't have to guess. I looked it up, and you're right.
This is a little bit of a guess, but my first interpretation of that is that hosting goes under "Cost of revenue" and most of "Research and development" and "General and administrative" is salaries. I.e. that they pay spez's friends something concordant with the $139m that they paid spez personally last year.
Yeah. On page 11 it says they paid out $577m in "stock-based compensation". I don't know exactly what that means but it kind of looks like all that whining Spez was doing to the Apollo devs about how Reddit can't turn a profit with them out there charging $3 for their app or whatever, just meant "MORE, MORE FOR ME, I WANT MORE, IT'S NOT ENOUGH IT'S NEVER ENOUGH."
God damn dude, I should start a social media company.