What kind of factors in an mmorpg that isn't very popular keep you playing and supporting it?
For me it's community and GM support, and in cases like that it's possibly preferred for the game to be less popular so the few people there tend to know each other well.
Of course that's backfires when the game can't make enough money to stay online because of lack of paying customers. >.<
At this time I'm finding myself fond of Remnant Knights at LEAST because the people in charge are very active, friendly, and helpful.
I was testing this game past midnight (central time) and they were STILL having little mini events going on with the GM and few people online at that hour.
AND I reported a "bug" in the forums (turns out it was just my keyboard though) and I got great help very quickly.