I'm sorry you didn't have a good experience with our toolbar. The false positive rate is actually very low, but there is a subset of sites (new launches) where we still have some problems. Basically there is a time lag in our crawling. Unfortunately, this effects the HN (startup) crowd more than others.
A lot of people want to avoid parked domains and ads, hence the popularity of noscript. You do not appear to be one of these people :). So it probably wasn't for you in the first place.
It blocked maybe one "junk" domain and false positived on three.
And really, it's an even worse idea than NoScript - what harm is seeing ads on a parked domain going to do you every now and then?