In nearly every one of my Summit classes, somebody asks the question about how to turn off personal portals and yet allow people to manage their SharePoint portal alerts. Microsoft didn't make it easy to do this because personal portals is one of the main features of SharePoint Portal Server 2003.
You can handle this one of two ways:
1. Completely turn off personal portals. To do this, you also need to bypass user profile importations and avoid using audiences. If the profiles aren't imported, then personal portals won't be created. Also, you'll need to disable three rights:
Ø Create Personal Site
Ø Use Personal Features
The problem with this approach is that users must use the Outlook client’s Rules and Alerts feature to manage their alerts. I've successfully managed portal alerts using this feature, so it's worth a look. It will also work in a Windows SharePoint Services only environment.
2. Turn off the Create Personal Site right, but leave on the User Personal Features right. After importing the user profiles, the users will be able to click on My Site, and use a *non-collaborative* personal portal to manage their portal alerts. You might want to test this out to see if it meets your needs.
Because personal portals are really tied closely to a portal implementation, I honestly feel the better way to manage them is to allow them and educate users on how to use them rather than attempt to turn them off. This is, IMHO, one of the key reasons to purchase portal server in the first place.