The alert banner shows the number of links tagged for you. It will not display if there are no links for you that are unread. There is a link in the banner that will take you directly to the 'links for you' page.
The alert uses the user id of the last login into del.icio.us. It also requires that you are currently logged into del.icio.us. If there is no recent login information or you are not logged in then a message will show in the banner requesting a login. This message includes a link to the del.icio.us login.
In my mind to make this a 1.0 version I would like to include the functionality to store the read/unread status on a server instead of locally in GM variables.
bg