It's like a backpage section for escorts; everyone wants to use fancy language and cute fonts to attract attention but when you get to the basics, every listing is for (more often than not) the same thing.
Every world I've seen a posting for in classifieds has a MWR, anti-tanking measures, great core group of loyal owners, fun atmosphere, competitive but good-natured world chat, etc. etc.
I think it ends up being luck, if somebody sees your ad first and is looking for a team, they may poke around at a couple others but if nothing seems wrong with your league then it's going to be the chosen one.
And yes I have posted a classified, albeit only once (not counting when looking for replacement owners), but I check it periodically and see the same threads just being bumped on a daily basis. My world had 3 openings at rollover; I sitemailed a guy who had owned a previous team in the league for like 20 seasons but left a couple seasons ago and asked if he had any interest in coming back to his team, got no response. Put up a classified ad, I believed we bumped it a total of 3 times in one week, and included franchise links in the post (one of which has the 1st overall pick and another with 4th overall, both attractive options to any newcomer) and then the private world restriction ran out and I decided not to keep it private. Once we showed up on the public world list, it took two days to fill, including two owners who have never played (or are using an alias.)
If they are new owners and we can help them with our knowledge and create a fun atmosphere for them, then I'd feel much more proud than I would have if the openings went to someone who already has 6 teams and can't have the time to be as dedicated as owners with less teams. To further go with my point, I definitely think any true new owner will not check "Forums" nor go to "Classifieds" before joining a public world if they are presented with that option.