One problem as I see it is that Self-help as a community driven thing never really took off here. I think a big reason why is the perceived high bar to post quality. Self-help involves engaging with lots of idle weird ideas that don't work out before you hit on something useful. I'll also note that most of the online communities that really seem to be "communities" have an off-topic area that attracts a lot of posts where people feel free to be more casual. When brought up in the context of LW people point to the IRC chatroom, but that is a very different type of interaction.