FOR THE INDIE IN ALL OF US (Hypebot) – It doesn't seem like it matters now. You just want to get as many emails on your list as possible. But as the list grows knowing who is on it and where they are from will start to matter.
Your band swings through the South (or just a neighboring state or off to NYC) a couple of times a year and you really want to build that fan base. Do you think you accomplish that by filling their inbox with last minute set time changes for a show 1500 miles away? How many unsubscribes does each of those intrusions cause?
From the very beginning, make it simple to sign up for your email list, but also ask them who they are. Talk to your webmaster. Various email programs offer different solutions like just asking the state or a zip code without demanding a full address. Some like the free tool at ReverbNation, add a kind of geo-targeting that can tell where the ISP is that your fan uses. But it works only if an email is opened and is not 100% accurate; so that should be a secondary option.
If getting to know your fans is a goal – and it needs to be – knowing where they live is a great place to start.