User blog comment:CocoaZen/What do you think about blogs freezing after 30 days?/@comment-824313-20120403025428

I think in general it's a good idea. The idea of keeping people from accidentally trying to join burnt-out conversations is good, although I agree that there could be a better way to do it, such as a warning of some sort instead of a freeze.

Note that the creator of a blog post can turn of commenting at any time by editing it and deselecting the checkbox in the sidebar (or toolbar if you're using widescreen mode), so that might be why you're seeing blogs frozen before those 30 days are up.