My money is on facebook growing even more, especially once the IPO happens. But...remember what happened to AOL. They came from behind to overtake Compuserve, GEnie, and Prodigy to become the biggest online service company. Grew too fast. And it all imploded on them for one reason or another, including the explosion of the Web, and the idea that everything they offered for a stiff monthly fee was more or less available for free, and with unlimited bandwidth, on the Internet-at-large. During peak usage, I was shelling out around $50/month with Compuserve, and at best, I was comped for access to one area since I was a sysop. In comparison, my first dial-up account was $15/month, and I could putz around online for as long as I wanted. Back then, nobody even figured that you could get online and not have to belong to one of the big service providers out there.
I just think there are too many social media sites out there. Instagram is cool, but if I'm signed up for a half dozen other social media services, why would my friends want to "befriend" me at yet another service? It gets old. Nobody can agree on any one service they want to all join up at--I personally avoid facebook for numerous reasons, yet only some of them want to join me on G+ or
Path. I'm actually liking Twitter more as I have increased usage: 140 characters, no strings attached, and my accounts are either public or private (aka "protected").
My gut instinct is that there will be a major shake-out. Someone like facebook will implode for getting too big, too fast, and getting too many people PO'ed at their lack of respect for member privacy. It is not like members will then flock to G+ or another service (as they did when MySpace became redundant)--something completely different may come along to replace the existing sites, a way we can network yet remain free of any one particular service.
