Yes i have but not too big . this systems helps you to know who visited your site than you can also check their site and do post comments over there . You will get some good bump in traffic by doing so .
My blog has been in MyBlogLogs Hot community page, http://www.mybloglog.com/buzz/community/, for about a week now. I almost get 10-15 hits a day from them there. Yippie
Nothing really. I added their widget to my sidebar so you can see who the recent visitors are, and I guess people are just using the "Add Me To This Sites Community" link that is on it. My only guess is that I am getting more people adding than others sites right now.
Blog Catalog works better for me, as I can choose a community where I can start a thread. At Mybloglog, visitors are like droppers from Entrecard so bounce rate is high...