[hyp0]

What will they use the money for? If they're not expanding, and are profitable (and so don't need to cover running costs), I can only guess at retiring founder debt.

[SurfScore]

They said they aren't profitable, they're hiring too quickly for that. They're using the money to hire quicker, just like most other people use investment for.

[mhartl]

They're expanding. It's a land grab, so gaining market share is more important than profitability. Spolsky wrote about it here: http://www.joelonsoftware.com/items/2010/02/14.html