Agreed. I have been one of those people no longer excited about social networking for some time, and I find that Facebook has lost a lot of its' value. The only thing keeping me from leaving it is all the people and family I left when I transferred schools, and how easy it is to stay in contact with them. These sites are still an adequate tool for maintaining such relationships, but it can be frustrating to do so with all the mindless junk that gets mixed in.
What is sad yet no less true is that sites like Facebook are seen as a requirement for being a social person. Being an introverted person, this fact seems to glare at me the more I use Facebook. I have tried being the social person that "shares" with everyone, but anymore I find myself cherishing the genuine human contact I receive from actually talking to people. Sure Facebook is great for wasting a couple minutes to catch up with everything going on in your world. But its good for no more than that. Life truly is more fulfilling when you just close that tab, and do something else. I'm not leaving it, just leaving it alone.