[jol]

for me: what is that "a lot more"? I just want to learn something new (btw, labels/tags are not really new, just redesigned imap folders)

[omh]

Tags have an important difference from folders in that messages can have multiple tags and you don't think of messages as being in a folder.

Personally I find this quite useful and it definitely improved the way I use email.

[pbhjpbhj]

Opera Mail had tags quite early on, not sure if it was before Gmail though.

[hugofirth]

Non trivial statistical analysis of email contents and your interactions with your email to effect decent prioritisation?

That would be my top feature in gmail.