I disagree with this. Yes, search might be necessary, but there are plenty of other options and it isn't as if there is anything stopping you from using another

I disagree with this. Yes, search might be necessary, but there are plenty of other options and it isn't as if there is anything stopping you from using another. (Bing has many of the same features as Google now) Facebook is different because they are locking you in (perhaps inadvertently) by having all of your real life friends already in the network. People feel forced because it's the only network that is nearly ubiquitous.