Who determines if something is official

I don't know the legal answer but will suggest that I think it would be in the eye of the "beholder"...and in this case, the band.

I can't imagine anyone other than them complaining of the use of the word Official...so I'd suggest asking the band flat out if they would mind your calling it that...

You could just take your chances and put it up that way...but you'd risk their thinking less of you if they did not like you calling it that...and it sounds like they DO appreciate you...so I'd just ask them.

The bonus of contacting them is, if they agree, they could put you in touch with their marketing for exclusive content.

The only one that can term something as official (in a case like this) is the object of the site. It is up to the band to give this designation. Since you have established a rapport with them, simply ask if you can list your stie as the official fan site. But do it first before one of your competitors gets the idea.

You may have a couple of points in your favor, if you registered a domain name, you have the date of registration to allow you to state you were the first (assuming that's true). You also have notes from the band, hopefully dated.

I have a similar situation with a website I run. I asked the person that the site was about whether it could be dubbed 'official' but he said he preferred it as it was because it felt much more personal. I also guess there could be the issue that the person running the website could try and charge the object of the site for the pleasure so they may be wary about that! The best thing to do would be ask the band, and if they say yes, then all's well. If they'd prefer NOT to have an official fan site, then ask if you can have some contacts from them (PR people, PA's, Agents etc) so at least if there are lots of other websites out there, yours will have all the information first off, and you'll receive loads of goodies to review etc!

Good luck!