As you seem very experienced in this, let me ask you: what do you think about those who stick the first post over and over on all the pages of that thread in their forums instead?
My point of view is that would cause "duplicate-content" in SEO Terms, but based on your previous post, it could also indirectly increase the revenue then?
I'm not talking about my specific case but in general, as the forum I'm running is set-up to encourage interaction, so users don't tend to write posts like "me too" or "that's cool" but, exactly like the post we're actually writing in, users tend to write longer and informative posts, all related to the main subject.
I've always seen things in the users' perspective and worked on giving them an always better user-experience, but I guess a website also needs a good strategy about monetization.
If you're wondering about me, I'm in the top 3 with 17k messages in 7 years, but that's only because I really like and enjoy personally taking part in the forum's activity, and I like to put everyone at the same level, admin included, so when there's someone asking for help, I'm there, too
Getting back on the topic, there's something I'd like to point out. I'm not going against Xenforo, as I really like it and I'd never go back, but before using Xenforo, I was using another platform (phpBB), but I recall Adsense doing a lot better on there
Maybe I just customized Xenforo too much, causing all this mess by myself.