One of the benefits of this is that if you change your email address, all you have to do is change it in your account profile, rather than the present system of having to remember which diaries you're set to receive notifications from, unsubscribe one address and resubscribe a new address.
You'll of course need to verify that you're the owner of the account you're saying you want to be a friend, and that will be done in a similar way to authenticated comments at present. Since you're authenticated there'll be no need to 'confirm' your request to be on a Notify List, so there'll be no more 'Unknown Unique ID - please contact support' errors.
An extra benefit of this will be that you'll be able to see who's diaries you're marked as a friend of (whereas the current notify system doesn't allow you to see who you're set to receive notifications from!).
The diarist will be able to refuse to send you notifications however, with a screen of their own showing who has set them to be a friend.
This will be the first of a number of enhancements utilizing the new 'friends' system, which will hopefully include such cool things as providing the drop down list that some people manually make on their diaries at present linking out to other diaries; and the ability to mark entries as readable only by friends... I don't know the timescales for these other two yet - but the friend notification system will be coming within the next week or so. When it does come, all existing 'notify lists' will BE REMOVED and you WILL need to resubmit yourself to the diaries that you wish to be considered a friend of (and therefore able to receive notifies).
If anyone has any suggestions, or thinks of something I may have missed with the new system please feel free to drop me a line!
Steve.