You can always comment in there profile under there journal or comments section. You can also post questions on the borads.
I can't belive that bolt once had a book called the "tagbook book?" but, now when you go to their website there isn't a single place to tag people. It's like a step backwords for bolt if you ask me.
http://www.thefirstgeneration.com/ is the best site that I have heard of that is comparible to bolt2. They have tagbooks their too.
Blogs were completely different from the tagbooks from the original bolt, because of the fact that the "Blogs" here on the new bolt are the old Journal Entries from the original bolt, but in a sense i can see the fact that the blogs can be something of a tagbook.