It looks like Blekko might be including nofollow links if the rel attribute isn't identical to "nofollow", for example on Twitter user profile URLs it's rel="me nofollow". Definitely a bug though.
I've just confirmed the nofollow behavior with Rich at Blekko. Sorry, it does make the results a lot less useful as a guide to what Google's taking into account (along with all the other disclaimers!). I'll be updating the blog post to reflect this.