I find that I use Sythe more if I play Runescape more. If I am playing rs then I usually go on to Sythe and browse around, but during the periods when I don't play rs (a few months each year), I hardly use Sythe at all.
I have had weeks when I just log on once and generally I don't post as much as I used to but taking a break is kind of relaxing. If your activity is seriously affecting your real life though then you have some issues. It's just a forum site.
Normally when im on the computer at home i have sythe open just to check the off-topic sections but yeah im not too involved with many here, apart from the ones who play the same games i do.