User blog comment:Toughpigs/Wikia's new Forum demo/@comment-26686429-20120726000727

"Discussions are threaded, so you can follow individual conversations rather than pages with multiple conversations"

Whilst this is certainly true for user talk pages, this isn't true for forums, where each different discussion has it's own forum topic. If you're talking about topics being derailed, this system is worse than that, as you can't use indents to reply to an individual person.