Inevitably people have started speculating about what it might do with the money, assuming the speculation is right and it does actually go for a listing. News site V3 has Goldman Sachs predicting that the valuation is right and that it may push into other territories, although 10% of the world's population already uses the service; it also suggests it might push into monetising its services further. It warns of a lack of focus.
AcquisitionsThere is certainly a case for saying it's not likely to get more than 10% of the people in the world using it as a network - that's a huge number and you have to ask whether it's reached saturation point yet. It can't be far off.
On the other hand why bother? Acquiring companies for the sake of it is certainly a passion for some companies but it doesn't necessarily make a lot of business sense. And a combined Facebook/Twitter - let's call it Fritter, after what people would do with their time using it - would almost certainly have the monopolies and mergers/EU competition people/American FTC onto it about a monopoly in social media.
It's strange to watch companies that become this big - you have to ask: what will it do next, now that it's already the biggest in its field?