I feel the same about people who do use facebook, when they take pictures of me and others who are not on "The Social Network", then they put those on facebook for others to see with other personal information without concent, they don't inform me about their comments regarding those pictures.
For all I know those people could be making fun of me for not being on facebook, not being social enough, having unfashionable clothes etc. From my perspective those people have something to hide, they share information in closed groups, refuse to email me those photos and waive it away like it's too much work, I have even experienced this with some of my relatives which saddens me alot. I'm not forcing them to use any specific website, forcing others to do that is nasty, it's no different than forcing others to smoke by the means of social pressure.