What's strange about it? Facebook, twitter, ...., don't solve any tangible problem: they are generic social networks that are more subject to fashion than intrinsic value, because people to communicate and get in touch need very little: ability to send message, profiles with photos, and so on.<p>This is why I never understood the facebook buzz around tech people, for example here in YC news: it does not care. I don't want to state that only things like a search engine or a bug tracking system can care. Flickr cares a lot, changed the way people put photos online, is a social community in some way but driven by a common interest: it as a side effect it's a database of images.<p>The same like delicious, social bookmarking cares: it is a place where you can really find interesting resources, and it is useful for individuals. It is also one of the best applications for tags that is a very important semantic concept.<p>Instead generic social networks will came and go away one after the other, like Pubs do: they are mostly about fashion.