Not quite. The dividend technically hasn't been paid out yet. That'll happen sometime in December. In order to receive the one-time dividend, you had to own shares of Microsoft when the markets closed on Wednesday (I think. Might have been Tuesday). So, for all intents and purposes, that money is locked away and can't be spent. That is, Microsoft can't use those billions of dollars to acquire another company since they're already allocated to be paid out to shareholders. Hence the drop in share price leading up to the cutoff date.
There are two conflicting schools of thought regarding dividends. On the one hand, there are those investors who believe it's best to sell your shares prior to the dividend cutoff date. Actually, just prior to the decline leading up to the cutoff date. On the other hand, there are those investors who believe that you should hold onto your shares and accept the dividend payout (and the corresponding drop in share price). For the small-time investor, it's probably six of one, half a dozen of the other. Take your pick. But for larger investors with a substantial number of shares (think institutional investors and the like), tax implications might make one method more attractive than the other.
I'm not a financial analyst, though, so perhaps one will step up and elaborate.