Ya, OK I know Verticalization is not a real word. And when I coined the term "Vortals" (Vertical Portals 10 years ago, that wasn't a word either. Never the less, this is what has been happening, and will continue to happen on the web.
The "next" thing in Social Networking will be going Vertical. You and I are already members of these new social networks, we just do not know it yet. As an example, LinkedIn is quietly building a knowledge base (their database profiles,groups and even this Q&A). It is not a difficult process for LinkedIn (Facebook will do this as well) to "spin-off" vertically specific networks. Facebook knows most of their user's birth dates. As soon as they reached a critical mass (let's say 1M) of users that were 60 years old +, they could start a new network just for that demographic. Being a vertically specific network has financial benefits. The ability to target very specific groups allows them to charge more for their advertising - because it is more targeted... Unlike getting yet another offer to join yet another social network it will be as easy as a user simply "opting in" to join. Their info, friends,links,likes,etc will all be there waiting.”