It's probably not as bad as it seems - Valleywag has its numbers wrong, and in any case, it seems likely that SUP is just moving more of its operation to Russia. It does mean that there will be less development, and I'd imagine less support for English-speaking users, but it's unlikely to disappear completely at least in the immediate future.
Despite all that sensible sounding not-panicking, I have backed up my journal again with LJ Archive, and I'm in the process of transferring it to InsaneJournal using LJ Sec. If the whole thing does disappear (which it won't!), you'll be able to find me on IJ and Twitter as pickwick, and on FB if you know my real name. (I was going to back up at DeadJournal as well but it's invite-only...anyone got a spare invite going?)
matgb has a handy entry with a bunch of useful links, and a discussion of the proposed Dreamwidth replacement which has been on the cards for a while. liz_marcs has some general back-up how-tos, and brown_betty has a step-by-step guide to transferring your entries to another journal site. 