If the owner already speaks fluent Irish, then the group becomes a listserv, as he has no incentive to push people through a textbook, although he will answer any questions people throw up. This isn't exactly fair, a Kieran. Groups like Úrscéalta (
http://groups.yahoo.com/group/urscealta), Buntús Cainte (
http://groups.yahoo.com/group/buntuscainte) and Progress in Irish (
http://groups.yahoo.com/group/progressinirish) have taken their members through their books of choice in sensible measured steps and are still at it. These groups are very popular, and successful within the constraints of their chosen curriculum.
One need neither be fluent nor a learner to be an effective owner/moderator. One instead needs be a good motivator/faciliator, and harness the talents/enthusiasm of the membership.
At the end of the day, however, online study groups have the same weakness that a "real world" adult-orientated class has -- that is, as the weeks/months progress, some members inevitably fall behind due to the pressures of their "real world" lives. There are several other fine Yahoo groups which started out cohesively but went astray due in part to pressures like these. And if we factor in the use of difficult textbooks (i.e. Learning Irish, Dillon's TYI, etc.), poorly structured textbooks (Ó Sé's TYI) or dialectically confused textbooks (Tús Maith), the stresses on such groups expands exponentially.
A good owner/moderator can sometimes overcome the handicaps of their chosen textbook -- but sometimes not. Occasionally a "fresh start" is needed if a group has gone astray, which is occurring in a couple of the popular groups just now.
Yahoo groups (or other groups like them) are somewhat helpful to the student who otherwise would have only self-study materials with which to work. "Real world" classes and visits to the Gaeltacht are far better. We shouldn't purchase a bicycle and expect it will serve us as well as an auto. Online study groups are like a bicycle -- better than walking, but there are certainly faster ways to get your studies from point A to point B.
Abusing/berating the bike, the bicycle factory workers or the owner of the bike factory doesn't get you auto-like performance. If you're impatient about your progress, upgrade to better methods. Many others are content on their bikes, and motorheads just annoy them.
It is not important how many members these groups have. 3 committed members will create a lively group whereas 100 people who don't participate kill the group off. A small committed cadre certainly helps keep a group lively, but 100 quiet people cause no harm at all. Most such groups have as their majority people who prefer to "lurk". My PII group is like this, and we have certainly not been "killed off". Of 135 members, I think at least 110 have never posted. Some members admit to having fallen behind weeks ago, but the way the group functions allows for people to follow along later, and ask any questions they have, even if they pertain to an earlier lesson. Members have created crossword puzzles, practise threads, online flashcards, personal blogs whereon they practise their Irish, etc. Hardly a dead group.
In short, a Kieran, view the bike for what it is -- a bike. Some have nicer bells & whistles are are kept polished while others rust due to neglect. But they're still bikes. Your tone, both here and in other threads, implies that you want something more. Go get it.