Two jokers drop out of Goldman Sachs after a very short employment stint and hire some kid to build them a Facebook-based link-sharing game that targets emerging artists who have no money on the most garish website I've seen in quite some time and all he gets credited with is Lead Engineer. Not even Mr. Lead Engineer.
If non of the above doesn't embarrass you from turning down below-market deals with non-technical, inexperienced dreamers than nothing will. You need to recognize that your skill set is a finite commodity and the more time you spend on loser projects like these, the less in-demand you become. On the other hand, everyone knows that you'll do almost anything for cheap and you'll end up as the "coder dude" while the co-founders debate the merits of shitty internet-generated logotypes and branding as they plan their trips to SXSW.
tl;dr: Facebook-based link-sharing games are loser projects you need to avoid.