It's a common structure for purple especially. "_____ Something" or "Something ______". It means that the connection is that each word/phrase in that category works if you fill in the blank with that word. So today's is that "Attack Ad", "Personal Ad" (aka "the personals" section of a newspaper), "Pop-up Ad", and "Want Ad" (a term I'm not familiar with, but searching tells me it might be similar to a personal ad) are all phrases that exist.
An attack ad is an ad attacking someone. Usually used in politics. If your ad says "don't vote for X because they'll do this really bad thing", that's an attack ad. Sorry, I didn't define it in my previous comment because I thought it was widely known enough not to need the definition.