If you go to
http://www.livejournal.com/manage/logins.bml , you can see the recent login history for your account.
Yesterday a change was made that recorded incorrect IP addresses for a few hours. Probably a 172.something address. That is not our staff, just a screw-up on our part. [edit: The entries in your login history are not other people, we just recorded wrong information during a small window of time yesterday.]
As far as everything else goes, yesterday we pushed new code out to the website. I'm not completely sure of the full changes, but some things are buggy, and we've asked our developers to take some time to help us concentrate on performance.