I was really excited about flock, myself. It was actually pretty awesome and for a while it really helped me keep up with FB, flickr, and twitter better than I ever had before. Wrote about it a bit in my blog. But they were never able to keep pace with Firefox development. So I stopped using it and I think most others did. Last time I checked it out, they had switched to webkit, but I don't really use FB that much anymore and have other programs for flickr and twitter.