Here's an interesting infographic about Facebook usage. As you can see, Facebook is huge in the United States with 71% of internet users active on the network, but that's only the tip of the iceberg. 70% of Facebook's total user base is located outside the US.
The second item that grabs me is that the 18 to 24 year old demographic grew 74% last year, which seems to dispel the popular wisdom that Facebook has peaked.
One disturbing trend is that 48% of young Americans get their news from Facebook. Not a good sign for newspapers, radio and television news.
All in all, I'd say this makes a compelling case for an investment in next years public offering.