Recently, the social bookmarking site del.icio.us added the ability to tag a link for someone else's attention1. So if you tag a link as for:carlfish2, it will be placed in a 'private' RSS feed that only the intended user can retrieve.
While the feed of for:username links is protected from idle viewers, authentication is performed via an opaque token on the end of the URL. This means you can still share the pre-authenticated feed URL with anyone you want without compromising the account3.
This can be quite useful if you work for a small company full of people who tend to find useful things on the Internets4. All you do is register some arbitrary username, 'blah', and tell your co-workers that every time they find something on the web that they want to share with the rest of the team, they should post it to del.icio.us and tag it with for:blah.
Because the URL for the feed can be safely shared, you can stick it up on your Intranet, encourage your co-workers to subscribe to it in their own RSS readers, and so on. It's a lot more lightweight than emailing around links, both for the senders and the recipients.
The advantage of using a public service like del.icio.us instead of rolling your own link-tracking system is that people can make use of existing bookmarklets and rich clients for posting, and those people who already use del.icio.us don't have to deal with yet another place to copy every interesting link they find.
The disadvantages are that this approach would be unlikely to scale to a large number of participants, and of course someone could always use it to spam you.
1 An idea we intend to steal for Confluence at some point.
2 I don't read this particular feed, so don't bother. :)
3 Another one of those pending Confluence features.
4 "Internets" having recently replaced "Intarweb" as the trendy self-deprecating way to refer to the World Wide Web. I promise never to use it again.
