I'm not sure why I should reply to argumentative people who refuse to identify themselves even by a nickname, but if you're insinuating that only Mudcat members may use Esperanto, that's one of the silliest insinuations I've run across this week.
I'm a "member" of AA, too, and people seem to think that involves some sort of pledge.
In case you genuinely don't know, "PM" refers to a "backchannel" Personal Message from one Mudcat member (regardless of Esperantism or otherwise) to another.