Before I release b2 v0.5.2, I figured I might aswell fix three infamous bugs in v0.5.1, one that forbid the month of december to be shown from an archive link, one that didn't display the author's ID, and the a comments thing that forced people to fill all fields when commenting: look at the new default config file, there is a section named 'comments options' that has a variable to re-activate this feature, and a new variable to let you specify which tags you want to allow in the comments.
Update: I also included the page generation speed fixes.

Check the releases folder. If you're an existing user of b2, just replace your files with the files that are from december (except the default config file, of course).