New Social Sites Cater to People of a Certain Age

I've always been curious to see if social networks geared toward the older crowd will ever catch on. My concern with this is that while there may be as many internet users in the 55 year old range as the 18-34 crowd, will they be willing to invest a similar amount of time on these networks?

Something tells me that these people won't rely on these services as much as the younger crowd, but I could be wrong...