This was quite a test. I guessed outright on 30 of them (and got 16 of them wrong), but I managed a respectable 165 (out of a possible 200). According to the author of the website, this puts me in the top .2 percentile (99.8), based on his own experience (his score was identical to mine). A quick look at some of the bloggers and blog readers shows the high literacy level amogst the blogs that have participated; almost all of them are at 140 or higher, and my score falls right in the middle.
(Link courtesy of XRLQ. It appears that half the blogosphere has taken the test in the past two days.)