You'll find a lot of slang on slang websites and in slang dictionaries because, a lot of the time, anyone can enter a new word for the site (even if it's a word they just made up). So, even if only one person uses "pop tags" and they decide that it's slang they use often, they'll make a definition for it and put it on a site like Urban Dictionary. Also, if it is Urban Dictionary you're using, look at the thumbs up and thumbs down. If there are more thumbs down than thumbs up, chances are it's not common slang. I think the best way to ask your questions would be "What does _____ mean and is it used often?" Then people can give you their opinion. :) As for "pop tags", I've never heard it and I wouldn't use it myself.

Meaning of "pop tags " I see that you got it straight from www.urbandictionary.com "When you have so much money that all you do is buy clothing. Therefore you are constantly popping tags off your merchandise. check my restroom trash all I do is pop tags"

They are tags that go "pop".

i learn something new everyday :P