Those are indeed the anti-adblocker decoy posts. A random number are inserted before and after ads. This and several other tricks make it impossible for Adblock Plus to block forum ads (if the advertisers follow certain guidelines) without also completely breaking the site.
I wonder why more sites don't bypass ABP. In fact, I don't know of any others that bypass ABP without outright preventing ABP users from using the site. It's somewhat difficult to arrange the page layout so that it works, and you can't use any external JS or images for ads, but you'd think that the increased value to advertisers (and therefore increased ad revenue) would be worthwhile for many sites. Bypassing ABP is especially easy on sites that require JavaScript, since you can just directly undo what ABP does instead of trying to prevent them from being able to do it in the first place.
90%+ of sites will use a publishing network which will ban them for trying to 'force' the ads on them. Its a rarity that a site direct sells its own ads.