Coldplay are another band who are doing interesting things online. (Again, like U2, maybe more interesting online than on record, but again let's not go there)
They currently have 235,000 followers on twitter, they have a roadie blogging the world tour, but best of all I think is the Oracle.
The Oracle is a question and answer service for fans. Fans ask questions, the Oracle answers them promptly. For example:
"Q. Hi Oracle, Do you really read all questions? What does Chris say at beginning of Til Kingdom Come?... "Wantoo?"
A. Yes I do. He's saying one, two. (I made a little rhyme there see?)"
"Q. Dear Oracle!I'd like to go to Italy (Udine) to the Coldplay concert but I don't understand the "ticket's names" 'coz I didn't learn Italian language.So please help me! Which is the standing ticket?
-Gradinata Numerata Intero
-Prato Non Numerato Intero
-Curva Nord Non Numerata Intero
thank you for your help
A. You'll need to buy the "Prato" tickets."
"Q. Chris and Will were both wearing (very) cool duds last night in Melbourne. What's the label with the "V" on the long sleeve tees?
A. Do you know I think there's strong possibility they're both from Topman! The V was painted on though it's just a customized tee so you could technically get one from anywhere but if it really is, as I suspect, Topman then affordable to all - hoorah!"
OK, not rocket science, but I can't think of any other companies that do this in such an engaging way, let alone other bands.