I stopped doing that 12 months ago since most of the sites just disappeared into the back and beyond end of serps. I don't know if it's justified but I am fearful of doing it, so I haven't.
Edite: Just realised that the last dom in my sig was one of them, I've just built a new site & put plenty of content on so it'll be interesting to see if that comes back from the arse end of goog.