Signing on to multiple Bryght sites with one username
Bryght sites and other Drupal-powered sites with the drupal module enabled let you sign in to those sites with one username and password, saving you from having to remember multiple username and password combinations.
The first time you you create an account with a site with the distributed authentication functionality enabled, the email sent to you will show the username to use for each other site that has distributed authentication enabled. That username--called your "Drupal ID"--generally takes the form of username@www.sitedomain.com, where username is your full username (including spaces), and www.sitedomain.com is the web addresss of the site you originally signed up at.
Note that you will not have the same permissions at the new site as you did at the original site you logged in at. On the new site you login to using your Drupal ID, you will get whatever permissions that the administrator of the new site grants new users.
An Example
If a user named Joe Smith registers the user name "Joe Smith" (without quotes) at Urban Vancouver, which has distributed authentication enabled, Joe will be able to log on to Bryght.com, which also has distributed authentication enabled. To log in to Bryght.com, he would type in the username "Joe Smith@www.urbanvancouver.com" (without the quotes) and the password he used at Urban Vancouver. Bryght.com looks at www.urbanvancouver.com for the user "Joe Smith" and checks the password that Joe gave. If Joe gave the correct password, Bryght.com creates the account "Joe Smith@www.urbanvancouver.com" on its (that is, Bryght's) server with the same password.
A note about Drupal ID's: although the user name looks like an email address, an email account is not created on any server. It is just a simple way for Drupal-powered sites to determine what site a user has an existing account on, so in this case, Bryght.com checks www.urbanvancouver.com for "Joe Smith". All of the checking happens in the background, so to you the user, it looks like the user is logging on with one account, which is in fact effectively the case.