I think yabu to be glad people will be paying to use it (although the rumour has been doing the rounds for years and is unlikely to come to anything). If your dh really is addicted then I imagine he would be willing to pay anyway.
But I do think that social networking sites have taken off so fast, that we have't really thought of the consequences of using them.
We already have perspective employers finding their perspective staff on facebook, looking to see if they have incriminating photo's, I know of people who have been sacked both for their use of facebook and for saying derogatory things on there. The problem is that people have so many "friends" that often they forget who is actually reading their status updates. Yes it's possible to set your settings, but the reality is that most people don't do that until it's too late.
Actually I think a lot of that applies to mn and any other public forum, where people post identifyable information about themselves forgetting that the internet isn't really anonomous even if you are posting under a username. TBH I don't know what the answer really is, or whether it will just take time for people to stop being quite so open on the net, whether that be facebook or otherwise.
Fwiw I am on facebook, I don't use any of the applications (none of them are accessible anyway but I don't see the point,) but I have found friends there who I had lost touch with for years.
I think it has its place, I think that reading about other peoples' statuses is part of how the future is going to be, and that in the not too distant future not being on facebook will almost be like not having a mobile phone.