I have witnessed this too, and some of the lists I read most tend to be the
smaller ones. I also find that the archives of some of the bigger lists are
very difficult to search. I find nettime a pain to find stuff on and I know
others do too, which is really annoying because I wasn't online during some
of the debates most relevant to my research, and I can't sit around waiting
for them to published in books now can I?!
When there is no archive, they become more like Left Bank Coffee Houses etc
and this is a very interesting arena in itself, perhaps where just having
the discussions and conversations is what counts...and laying testament
occurs in the art works or outcomes of such conversations....
Do you find these lists more fruitful for the production of work? Do they
foster workable collaborations?