Whether or not it is a waste of time is your own decision. I find my time on the forums really enjoyable, and even though I know I could be doing better, more productive things, it’s like a place to relax, and I have fun talking to people. I’ve spent 360 hours on the forums, and I think they’ve been spent fairly well.
If you’re cutting things in your non-realm life, like friends, family, or your own health, to be on the forums, then I advise you cut back on your foruming, but otherwise, you’ll be fine.
The forums, and really, any activity, are places where your time is used the way you want to use it, and the result of the time spent is very much up to you to decide through your posts and actions.