I don’t really get the point on the Google IPO. To my knowledge (but I’m just a Computer Scientist, not an economist, so shoot me), the tihng about an IPO is going public (hence the name) and getting money (but you loose your company (or at least a part of it)).
Why would you do that? When you need the money (to grow, to buy other companies, to pay your debt, whatever). The question thus is: does Google need the money? What can money buy them? They don’t really have to invest mega amounts of money for improving their product, it is already the best there is. Besides, they do make profit (at least, that’s what I read everywere), so I don’t really see the benefit.
Another reason is that you think that your company is at its peak, that it will not become worth more. I think that this might be a more probable reason. What has google to gain in the websearch industry? Nothing. What has google to lose? Everything. Especially, now that MS is stepping into the searching businness more seriously, Google might get it much harder in the near future. So, from the owners point of view, it might be a good time to cash.
So, my advice: don’t buy.