The value of time spent is in the eye of the beholder.
Are forums a waste of time

Forums add to the sense of community. Yes even if we argue at least we gain some sense of who we are.
Most of the forum stuff won't help your chess much, is it a waste of time if you're having fun though?
There are quite a lot of useful threads imo, game analysis, openings, endgames, puzzles.
they are adictive... i don't know why though
Well, if you have a certain hobby that you really like, talking/discussing about it is fun as well. (at least for me)
If it's something you're passionate about, you're way more commited to the discusion.
Objectively, studying things deeply probably is way better than posting some general stuff on the forums. like i could have studied a dvoretski endgame instead of posting in this thread.
In reality though, if I didn't spend the time to reply on this thread I'd probably would have watched some eipsodes of some tv-show instead...
Truely improving requires a lot of work, it's just hard to do unless you have some big motivation, you improve by looking at your weaknesses which is painfull and hard.
I've spent time on a thread to figure out the worst possible 1st move for white, spent time explaining why some random youtube teacher is bad, spent a lot of time on a chess rap thread. I don't think that's wasted time, I had fun with it and even if I used that time to study hard I wouldn't be that good.
This doens't apply to all forums like I said before. you can get a lot of useful tips if you post your games in the game analysis forum. You can post a topic about some opening and the next day you'll find someone like IM Phren commented explaining on why he thinks your line is good/bad. That's just very useful, not many of us have an IM friend to give insights like that.

This thread isn't a waste of time
http://www.chess.com/forum/view/off-topic/its-official---chess-can-improve-your-mojo
gives you an excuse to play more chess

yes i know you may think this is funny but do you think that they are? I mean are they improving your chess skills or are they just a time sucker. your thoughts forum monster?
Not sure. Of course you can learn some things for "game analysis", or "endgame study" etc, but there are also some topics that are made just for discussion and game sharing. I don't tell that I don't like them (I participate is some of them). I say that you can both improve and spend your time
Forums are efficient tools for those with time to waste.
It´s a bad thing when you have limited time for "chess" and you spend half of it reading the forum.