What is Facebook IPO?

What would Facebook's IPO in late 2012 mean realistically for new employees hired in 2012?

• For those employees hired just before and say just after the IPO? It seems like already the effects are the equity amounts are low but there's a huge cash signing bonus: What else?  I'm assuming since the RSUs won't have vested by the time the IPO lock-up period is over, their liquidity wouldn't be impacted.  Will the salary/bonus amounts increase after the IPO because of less potential interest?  Or will the RSU amounts increase because the IPO will raise the stock price by multiples, and thus Facebook can afford to give out fewer of them?

• Answer:

  They will know exactly how much any stock offered to them in their compensation package is worth. Aside from that, it realistically means nothing since the company culture, activity, and compensation remain largely unchanged.