So, I think the bigger problem is not the main/discussion split. It's that, when coming to the site, one doesn't even understand that this is a forum!

I don't know if this is by design, but I was a LessWrong reader for more than a year (!) before I ventured over to the discussion section, and this was largely because I didn't see the link. I realised people were posting things because of the changing articles on the home page, but the same posts kept appearing so I figured there wasn't that much material.

It was only after meeting a few fellow LW'ers at a meetup that I realised there was a real community.

I don't know if I'm typical. It's possible I just wasn't really looking, it's possible I didn't care enough. But I am a pretty technologically savvy user (programmer for 18 years), and I've been around HN/Stack Overflow/Reddit for a long time, so if it isn't clear to me that there is a whole world of discussion here, then I'm sure it's not clear to most people. If this is by design, cool. If not, then there's a big problem here.