Basically, there is a field called Product Family on each customer's User record which lists the products for which they have active entitlements (i.e. maintenance contracts), and that field is utilized to determine the advisories for which a user should be notified, assuming they haven't unsubscribed to them.

For example, the user in the screenshot below has "RSA SECURID; RSA SECURID ACCESS;" as the Product Family value, which means he will receive email notifications for advisories associated with SecurID and ID Plus (fka SecurID Access) but not for G&L.

There is not currently a way to manually subscribe to advisories for which you (as a customer) do not have an active maintenance contract, but this is a functionality we are exploring how to implement in a future release.

The best way to help new customers to get subscribed to the appropriate content is to ensure that they register with the appropriate UCID, serial number, or contract number that is associated with their primary account (for those that have multiple), and this will ensure their user record gets associated with their active entitlements

The best thing to do would be to ensure the customer registers using one of their serial numbers, or using a UCID that is associated with active entitlements. As long as they do this, they will get email notifications for advisories that are published.