Groups is also offered as part of Google Apps, where it's actually useful (as internal mailinglists with web-based archive) since it's a closed environment.

In the last year Groups has had pretty significant work done on improvements. A complete new AJAX based design, better moderation controls for forum owners, and even Q&A features that are being tested in some Google Support forums.

I'm not convinced the new AJAX interface is a big improvement, and the old interface was already not particularly great.

Google abandoned "Google" Groups (Usenet belongs to Google?) years ago and gave in to spammers.

I think the 'Google Groups' name refers more to being a Google search engine that searches groups (similar to 'Google Photos' or 'Google Videos').

Google Groups isn't just Usenet either -- they also allow creating private and public groups similar to Yahoo Groups.

Yea, there was a period of time where it sucked (I remembered it too), but now it is much better.

It still seems to be the easiest way to setup and manage a small mailing list. I don't need more features and we just got a big UI update.

yes. This is under active development https://groups.google.com/forum/#!overview