I got (and get) spoilered all the time. I blame Cangel, cos, you know, I would walk into her room when she was watching some episode I hadn't seen yet, all the time. Also, I first watched s6 and 7, so all the main things (Angel going evil, dying, being ressurected, Spike going good, Buffy dying, twice.. and so on, and so forth) I already knew when I started at the beginning.
With Angel, I'm more careful, but then again, I've already seen s5, so the whole Connor thing, for example, is no news for me. And being online here, hasn't helped either. Now I know the general outlines of what will happen, but I'm staying as far away as possible from the details. Or at least, I'm trying.
Also, on the subject of spoilers, those little descriptions on each season on here, they give away alot, right? I know there are people here (like, let's see... me) who haven't watched everything yet, and it's difficult to avoid the main page..