They do not use any mailing lists at all as far as I know. At least I am not aware of existence of any mailing lists for ru.wp
First, as you (Yaroslav) is active here, I would like to know what Russian Wikipedians are using for communication. Just wiki? Some other ways of communication? Wikipedia in Russian is not a small project, as well as it is growing -- which demands some level of systematic coordination. I think that the answer on this question may be very significant at least in understanding some part of lists traffic decrease.
The main channel of communication is wiki: basically, the village pump which is structured as a number of pages, for instance for instance, general, news, rules, technical issues and such. So far it worked. Important issues are branched out as separate rfc's.
Some of the Wikipedians (not me) are full-time present on irc channel.
A creation of a mailing list for sysops only was recently proposed but was eventually rejected.
There is of course personal communication, and there are even some Wikipedians (not me again) who insist that most of the issues should be discussed privately.
The Russian chapter is in the creation stage and does not have its own communication channel as far as I know.
I am not aware of any other signifgicant communication channels (I recollect there is a collective blog which is half-dead and there is a decision of arbitration committee that this blog is not a part of the community), may be there are some more I do not know of, but it is unlikely. There are information channels of course, for instance, similar to wikizine. but they do not involve any discussions and are not widespread (at least now).
Some of the prominent ru.wp editors are subscribed to this list, I assume they will correct me if they have a different perspective.
Cheers Yaroslav