The general groups are for discussions about the NSLU2 and usage of custom firmware and packages, including: tech support, installation, usage, troubleshooting etc.
This list was originally for developer discussions but after too many end user questions got asked on it the list admin gave in and changed the charter. It is now for questions about running Linux on the NSLU2 but read the charter on the home page before posting and don't ask questions about setting up the standard Linksys firmware.
If you're compiling things on your NSLU2, by definition you're a developer and you should ask your questions on this list.
The mailing list for the Synology DS-101(g+) and its replacement firmware.
There is a dedicated mailing list for asterisk on the slug.
If you are using Debian on you NSLU2, you should now use the Debian lists instead of any of the lists described above. For details see:
Warning: the Debian lists are not spam-protected like the Yahoo-hosted NSLU2 lists. You might want to use some sort of "throw away" email address to post to them from.