Add ability for users to subscribe or watch to individual attachment updates

I went to a roadshow for Salesforce.com yesterday and one of the features of their product was a document management solution they have called "Content".

One feature they had which I would find useful was the ability to subscribe to individual attachments si that you were notified whenever a change was made.

Now I know that you can create a custom feed for a page to be notified whenever an attachment is changed but if a page had 10 attachments I may only want to know about changes to 2 of them.

For example, there is a page on EAC which the PST uses to attach all files relating to our webinars. Say Boots looks after the slides for the Confluence webinar. I download the file on Monday and subscribe to the attachment. Boots updates the file on Tuesday. I get a notification that the file has been updated so I can then download the latest version.

Not sure how much work is involved in this but I think it would be a great feature to have to boost our sales pitch of using Confluence to replace your shared network drive or document management system.