i recently looked at your advanced replication techniques in setting up multimaster replication. i would say great tutorial, but i think you already know that.
I had one issue though. I noticed it was included in the examples of more than two masters but not in the example of the replication between only two server. the line that was missing: server-log=mysql-bin. for some reason without adding that line the replication wouldn't work. you might want to ad that line to the tutorial. i think beginners might find it difficult to figure out what was wrong.
well keep up the good work!