I don't mean to discount Anthea's concerns nor the solutions
that have been put forward by the experienced listowners here,
but I'd like to at least toss into the discussion another
perspective (mine): Who's to say what's garbage and what's
the result of a community exercising its will?
 
I wonder if, in cases where a list starts to diverge from its stated
purpose, it is more a sign of a community in the process of change
rather than a degradation from a static standard. I own a list
that touches only occasionally on its stated topic. Some newcomers
object, but the list keeps growing steadily in size and traffic,
so I conclude that the discussion is satisfying enough to most folks
and don't meddle with it.
 
What's 'on task' and what's 'noise' or 'garbage' varies wildly.
Depends on who you ask. And on a list of 3000+ you got a whole
great big bunch of sensibilities represented. In this case,
taking steps to slow and redirect the discussion might be the
best thing. I just wanted to note that 'garbage' ain't necessarily
fatal to a list. Might be a sign of life, in fact.
 
--Eric Crump