Where as social is just that its whats cool/hip and something your friends are using. I think you underestimate the value of virility. Services like Instagram and Tumblr, are all very good services that are social and could possibly unseat what we see now. People and not just in the tech circle are always trying out new cool/hip social services. If some users think its cool, convince their friends to join and the cycle starts over.
Maybe. I think it varies with age group, as I was saying. I think people in their teen's and 20's are more interested in what's cool/hip. Certainly, for social services in that teen/20's demographic, I think you're right.
Older people, people with spouses, people with young children, people with mortgages, people with established careers and groups of friends and clubs and routines. Well, I think maybe the value of virility is less there. I'm not saying it's a good thing.
I don't know about this.
Firstly, I would have thought search users would be fickle; but people stick to Google: familiarity is a huge factor for mainstream consumer franchises (Buffett goes on about Coke, Wrigly Chewing Gum etc) as opposed to early-adopter tech folk; Google goes to enormous lengths for good PR and visibility (mainly by actually doing good, which is nice); despite complaints, Google does its job (relevant results; very fast), and keeps improving. If a commodity like search can be sticky, why not social media?
Secondly, a social networking service is intrinsically harder for users to change, because you are connected to other people. Of course, it has to do its basic job well; you have to keep improving it; you need good PR. In other words, it's your game to lose.
I'm not sure why MySpace failed, but I think part of it was targeting teens/young people (who like change, both in adopting the new and in then discarding it), e.g. via bands, which is also hit/fad oriented. I think facebook's uni students are less dangerous in this sense, because they more often want to keep in contact after graduating (compared with teenagers), and facebook have worked hard to grow out of that dangerously fashionable zone anyway.
warning: this post contains guesses.