What this means is that all content is now subject to Russian laws, where as up until now it was subject to American ones.
Whilst I will be the first to admit I know very little about internet laws in Russia, I do not think, like many people are already doing, that we need to panic.
Livejournal has been down sizing recently, and moving their servers to the same place as the rest of the company makes logical business sense.
For Non-Cyrillic users I don't think anything will change, but it may be worth backing up your journal content. An easy way to do this is to use the importer on dreamwidth:- https://www.dreamwidth.org/tools/import
It's never a bad thing to make a backup.
This post is currently a crosspost from dreamwidth to LJ, where I have been seeking out a friending (adding to my circle) a bunch of people that I am friends with on LJ.
Our main worry at this point, I believe is the that the mass exit of Russian users to other sites may push LJ into the red.
For now it's business as usual, though maybe if there's something you would hate to lose it would be worth saving it now.