OK! You’ve run across a Fan Collector widget for a band you really like. You would like to join their mailing list, such that you can stay informed as to their doings. Here’s how easy it is to sign yourself up.
First, an example of a webpage, with the widget embedded within. The widget is the item outlined in red:

To sign up for the mailing list, simply enter your email address…

…and click the ‘submit’ button. After a few moments, you should receive a confirmation:

If, rather than simply receive the postings from the band, you would also like to help to promote the band, then you probably would want to join the Street Team while signing up for the mail list. This can be accomplished by clicking the ‘join the Street Team’ checkbox after entering your email address and before clicking ‘submit’:

Again, this should lead to a confirmation after a few moments:

Whether signing up for the mail list, or both the Street Team and the mail list, your enrollment is not active util you acknowledge an opt-in email. Within moments, you should receive such an opt-in in the inbox corresponding to the email address you entered on the form. Here’s what to expect in that email:
From: Lee Thomas Band [mailto:joe@LeeThomasBand.com] Sent: Tuesday, October 13, 2009 1:23 PM To: ltb-ml-example@LeeThomasBand.com Subject: Verify your email to join the Lee Thomas Band mailing list ltb-ml-example@LeeThomasBand.com, Thanks for joining the mailing list! To complete the signup process, click on the link below http://www.reverbnation.com/<inscrutable key>&action_code=opt_in If you didn't request to join the mailing list, please click the link below and we won't bother you again. http://www.reverbnation.com/<inscrutable key> Thanks again for joining the mailing list! Lee Thomas Band Longmont, CO Privacy Policy: http://www.reverbnation.com/c./cms/PrivacyPolicy More Information: http://www.reverbnation.com/fanreach. Physical inquiries can be sent to: 501 Washington St. Suite J, Durham, NC, 27701, USA Unsubscribe: http://www.reverbnation.com/<inscrutable key> Report Abuse/Spam: http://www.reverbnation.com/<inscrutable key>
Click on the link in order to complete the signup process. If you are already logged into ReverbNation, that’s all there is to the process. Yay! You’re done!
If you are not logged into ReverbNation, your browser will be opened, and it will navigate to an information entry screen:

It appears that all this information is optional. However, it would be encouraged that you fill in as much information as you are comfortable in yielding. In this manner, the band is unlikely to spam you with a concert announcement for a Nome gig when you live in Sarasota. Also, ReverbNation implies that the Birthdate is required – likely in order to ensure the signee is at least 13 years of age. However, anecdotal evidence suggests that singup works just fine without this information.
Note that this is another opportunity to sign up for the Street Team.
That is all there is to it! The next time your favorite band sends a notice to their mail list, you will receive a copy!