LJ is going (against past assurances) to start purging inactive journals. They'll send a warning email, but some people are concerned because old RPG/charity event communities may be lost. Some communities have no active maintainers/members, but people still enjoy reading them.
Worse yet, IMO, is what might happen to journals of the deceased. I know I kept all of my mom's online accounts opened, as I enjoy seeing her pictures and sites, but I don't often go in and check her emails. I know a lot of my friends have friends or family members who have passed on, but who were very active on LJ. Losing those journals has a great potential for heartbreak and healing set-backs. If you'd like to be sure that those journals are placed on "memorial" status and untouched by this new purging rule, the information on how to do that is here.