I think everybody’s tool choices are driven mostly by personal preference. I mean, why use the tools you don’t prefer rather than the tools you prefer the most? At least that is what counts for me. I, for instance, don’t really like Twitter, I prefer Facebook. And if I have to choose to send a formal message to someone I would not prefer to do that via Facebook but via e-mail. So I think the choice of the tools you use is driven for the most by your personal preferences but also a bit by the social standards (e.g. It is not considered to be normal to send formal message via Facebook).
I also believe that everybody has his or her own preferences for the tools they use. Some people are fanatic at posting Tweets others aren’t. I don’t think one person can change my preferences of the tools if he or she tells me about it. I might take a look at the tools to see what they are but not much more than that. Unless it is a super tool, of course. But I do think that if enough people start using the same tool you are a kind of forced to start using it as well. Just look at Facebook, almost everybody has an account. If you don’t have a account you can’t see what is new, where the parties are or what your friends will be doing this weekend. So other people can change my views on the tools and might even be able to change it as long as I have a reason to change it.