Do you use tags?
I've disabled the tags feature on my ads. I've always found tags to be messy looking on any website. I took off the field when adding a new ad as well as the field in the actual ads.
You can see that it makes the ad listings look a little cleaner.
6 month old Vizsla Puppy | San Francisco Bay Area Dogs
I'm sure that it's better for SEO
to have tags but I'd rather have a cleaner looking site.