That’s malware. WordPress.com does not use text enhance or text link ads or pop-up ads or links in comments. If you are seeing those then that’s a browser-ad-on issue, or in some cases, it’s embedded into free games and/or toolbars downloaded from the internet. See here: Bloggers: Beware of Adware. http://onecoolsitebloggingtips.com/2012/09/14/bloggers-beware-of-adware/
You’re welcome. If you find that the links start appearing again you may have more work to do to get rid of them when trying to eliminate them as browser-adds. Some are extremely difficult to be shed of.