I'm very impressed with what I've seen of RoundCube so far. The software is open source, so maybe spamcop-specific features could be worked into it. I'd ditch Thunderbird if I could use RoundCube as spamcop's webmail.

I searched the forum and didn't see it mentioned. I know it'd be a huge project, but it's worth asking.

http://roundcube.net/ Things that would count against its immediate usage;

Project status: Beta
Latest release: v0.1-beta2
Last update: 2006-12-23
Project started: 2005-05-18

"mail filtering by rules, is not implemented yet"
"not compatible with users that reply to messages using outlook - missing all or part of messages in roundcube = unacceptable! "

System 'Requirements' are met
Install looks to be fairly basic (but that brings up other issues)
... lots of folks with problems
... a number of issues that boil down to 'simple' programming practices that weren't used / followed

Just from what I've read in their support Forum, Tracker, etc. .... I'd have to suggest that it's not really ready for a user-base as large as SpamCop.net .... I'm not even sure that I saw any signs of anyone using it thus far beyond folks with 'a few users' .... I could be wrong, just basing this on some of the questions asked, some of the issues raised ... pretty much folks dabbling around, sticking their toes into the water ....

No .... I don't speak for JT .. but .... with all the other stuff on his plate, I'm not impressed with it enough to send this upstream myself at this point. That 'some stuff could bee added / programmed in" is also the condition of the last attempted roll-out of the updated Horde/IMP package .. and that got undone pretty quickly ....

Wazoo -- that makes sense. They did just release their first stable version (almost a year after my first post )