IMHO LJ is pretty safe, for now - otherwise they wouldn't be expanding their services (all the time something new appears !) and especially getting rid of codes which helped to restrict the growth. But, of course, making an archive will never hurt, if your LJ entries are important to you (I'm practically never re-reading mine... it's also such a pain in the ass to search for something, since they are organized by the posting date and not by subject, so it doesn't make sense). As for the nifty LJ-archive program, will wait for the Linux version :)