I looked at that but you can't really get any feel for audience size from Technorati. If you could mashup a service like compete.com with Technorati then you would no doubt have a powerful tool. I was thinking of hiring someone to get started on a list. Who knows maybe there is a startup in it because it would be useful to marketing companies as well as startups.
I've been working on compiling this type of directory. When its finished its gonna go up at www.buzzfolder.com . Email office at unchartedventures dot com if you want me to let you know when i finish it. should be about a week now...