[tomxor]

It works as a tax free investment. So long as it actually pays off in the future, they get to skip tax by putting it straight into R&D now instead of tomorrow. Another thing they did was sell hardware below cost, so the public kind of benefit - but at the same time FB potentially benefit by undercutting competition and gaining market share... One way of framing that last one might be "Deciding how their tax is spent so that it might benefit Facebook" - from that perspective it doesn't seem like a bad idea (purely from the business side, not public interest) to burn the tax yourself for a little more control.