The Washington Post has an article today about 18 to 34-year-olds who refuse to sign up for social networking sites, much to the chagrin of their friends and significant others. How odd is this? According to the article, about 84 percent of 18 to 29-year-olds check a social networking site, such as Facebook, MySpace, or Twitter, at least once a week. The fastest-growing group of new Facebook users? According to Inside Facebook, it's women over 55.