"Domains RF" is a service that allows you to get a third level domain on the жж.рф domain zone. It might come in handy if your content is oriented on Russian audience and you want them to memorize your journal's name quickly and easily.
This option is available for every LJ user regardless of the type of his/her account. You can get a domain for your personal journal or for communities that you own. Moreover, you can purchase any number of domain names for a single community or personal journal. The purchased domain remains available all the time your account exists.
You can get yourself a жж.рф domain in the LJ shop
Read more at http://www.livejournal.com/support/faq/369.html?uselang=ru