I'm coming late to this thread. My view is that I do not have strong feelings about the threads themselves and can see from Objectivity's very eloquent posts, how they might help in extreme circumstances.
I dislike the car crash mentality of them - the excitement and drama. If people stopped long enough to think about what they are posting they might consider that suicide is a bleak act, and that the excitement is so terribly misplaced.
My main issue with the threads, however, is that in helping one individual, the lives of many others are potentially impacted in a horribly negative way. In the days and weeks following one of these threads one can almost chart the collective despair that pervades those at the very edge of being able to deal with it. A train of threads ensues, each one with its own tale of misery, despair and bleak hopelessness. It is almost as if the effort taken to support one member sucks the life out of many, many others. The most vulnerable of people in our midst are those that seem to end up bearing the brunt.
I think many of the works written about those making serious suicide attempts suggests that people in that situation would go out of their way to avoid being talked out of their death. On the other hand those making a cry for help type bid, come to rely on someone 'saving' them. It's a risky business relying on a talk board for that kind of action - a more interesting thread somewhere on the board or a less than exciting title and ... well help might never get to you.
It is complex and it is difficult to meet the needs of all of the vulnerable people who post here, but on balance I think for the greater good, these threads should be deleted and MNHQ should deal with them off board (involving known 'friends' of the OP as appropriate).