"Hacker alerts" are pretty common around DA and it has been for a long time. Journals warning you that there is a hacker loose at DA and will hack your account if you don't copy the journal and re-post it.
Some variations can be: "There is a hacker that will block all your friends, leave nasty comments on other's profiles, will deactivate your account, will get you in trouble with the staff, etc." another could be "Don't watch *insert deviant's name here* because they will give you a virus if you do" there are a lot more variations, but you get the idea. These journals always end with something like "If you read this warning, spread the word