There are a couple of destructive memes going around.
If you see a form written in Russian with a bunch of usernames, don't put in yours.
If you see a post with nothing but a link that says "This is very interesting", don't click it.
These memes exploit a hole in LJ security and automatically post to your journal. There's some discussion on closing the hole in
lj_dev here.
If one of these memes already got you, clear your cookies and change your password.
EDIT: Having read a little more about this problem, my advice is not to put in your username anywhere except LJ's own pages until this issue is resolved.
If you see a form written in Russian with a bunch of usernames, don't put in yours.
If you see a post with nothing but a link that says "This is very interesting", don't click it.
These memes exploit a hole in LJ security and automatically post to your journal. There's some discussion on closing the hole in
If one of these memes already got you, clear your cookies and change your password.
EDIT: Having read a little more about this problem, my advice is not to put in your username anywhere except LJ's own pages until this issue is resolved.