Livejournal made this promise too. "Forever" turned out to be... about eight years, before Brad got sick of learning that running a social media site mostly consists of moderating the horrible shit users will say to each other, and sold it to Six Apart, who then sold it to Russians.
eight years is not a bad run and the way the internet turns I sort of expect to have to jump to a different service around every five years or so because something turned to shit or shut down or...