Promoting a band through a website can be very valuable, or a complete waste of time.
If you aren't getting traffic to your website, then it can definitely be a waste of your time. If you are not getting returning visitors, it will also less successful than you would like. Fans are by nature returning visitors and they come back for new information, tour dates, new singles, etc. Therefore, you must give them a reason to come back.
Event Calendar
Even if you are a small band, playing the local Bar, or a bigger band, touring the nation, your fans, or potential fans, need to find you to enjoy your music. This is a huge way to increase the crowds at the local bar, and if you are getting a cut of the door, that means money in your pocket. Keep your fans aware of where you will be. If you don't play frequently, event notices on myspace, or email campaigns may be useful.
Music
Afterall, You are a band right? Your fans should be able to go to your website, and hear you. This may mean the latest single, or a classic cut, but there should be something there for them to enjoy. The more often you can change this track, the more often your fans will come back for more. All this can be monitored with some free utilities.
Newsletter Sign up
The newsletter sign up is essential to keeping in touch with your fans. Many people won't automatically return to your website after being there the first time. They may however sign up for a newsletter, if you have that feature available to them. Every now and then, you can send out a newsletter, let the fans know where you will be playing, if there is a new album out etc. This feature will pay off big time.
CD Sales
This is what it comes down to right? You want to get your CD into people's hands. With Paypal, or some of the other services out there like CafePress, that isn't very difficult. Fans are always willing to pay for a CD, and you bring them and sell them at your gigs, so they should be availible to them online.
Merchandise
Got anyone who is good with photoshop? Why not create a T-shirt design that you can sell through Cafe Press? You set the prices, and if you want to get them to your fans at no profit, then you can. But if you want to make $5 bucks on each t-shirt then you can do that as well, and use the check to pay for your internet hosting!
The features that i've written about are things that we can easily install if you need some help on your website. Contact us for more information.