The CPAN::Forum FAQ discusses mailing lists under "Why do I need this? We already have our mailing list!". They make some good points, but here are some more:

Plus. Currently the perlunit-users mailing list is hosted by SourceForge and has about 130 members with archives starting in 2001. If you wish to post without subscribing you're welcome, but your post will have to wait for moderator approval - he's the chap who sees and deletes spam so it doesn't go to the list.

Minus. For myself, I prefer a mail client with message threading, a local archive with tools for searching and sorting what's dealt with from the pending, a postpone facility, and a powerful editor (Emacs) for composing my text. Web forums don't give this, so I prefer to avoid them.

Grey. There are complications here already, and things will change in the future. It's not my place, even as current Test-Unit maintainer, to dictate your choice of discussion forum. I don't know what fraction of the project's mailing list subscribers still read their mail, or how many of them would follow this forum. There have been times when the mailing list moderator has not read his mail, so mail from non-subscribed people was not accepted. The ideal solution would be a transparent bidirectional mailing list to web forum gateway, but we're waiting for someone to unify our communication methods.

Summary. If you do post here, please also send a message to the mailing list and the current CPAN maintainer to let us know that you're here.
<username>@cpan.org will reach the current maintainer, look up the username on CPAN search.