Hello all.
The main site, as Joss has mentioned, uses disqus. Back in the days before the forum it was a busy old place with lots of discussion and I purchased a subscription to disqus. It kept everything under control as a comments system on the posts and also served as an in between forum type community and kept the cursed spam under control nicely. It does have some regulars that choose not to be part of the forum. Personal choice.