I think that the best approach I've seen is to this problem it to turn
the permission  ON and hide the My Site link. You could also alter the
default page of the My Site.

This comes up in every Admin summit class.

Here's where I've landed on this issue:

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.

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.