There’s a new feedback loop at mail.ru. This is a DKIM based FBL (like Yahoo) and is designed primarily for ESPs. I am hearing there is an IP based FBL for ISPs in the works, but there isn’t a firm release date for that yet.
Senders and ESPs can signup for the new FBL at http://postmaster.mail.ru/. One caveat is that you must have a mail.ru account in order to get access to the stats page and there isn’t currently an English webmail page. I tried but couldn’t get online translators to work on the signup page.