Drupal as a Social Bookmarking Service, your thoughts?

I see a need for Drupal to be able to act as a social bookmarking service, and I think it should be very easy to make a simple module to handle it. The basic functionality would be that a user (either authenticated or anonymous) would be able to post links to drupal with a simple "GET" form, either as a drupal form, or right from a url... For example:

http://example.com/bookmark/add?href="http://google.com"

This could bring a user to an input form that allows them to add a review (or it has already been added to add comments)., and then get redirected back to the page they were viewing.

Using the node system, things like fivestar, voting api, tags (taxonomy), etc would all be really easy to add as well.

You may ask with the hundred other bookmarking services out there, why would a site want it's own proprietary one? We have a specific need in that we have many non drupal sites in our network of sites and this functionality would allow people to register popular content on these other sites with drupal with a simple dynamic link like http://example.com/bookmark/add?href="http://google.com"

Secondly, you might say... ok , that's fine for content you own (and can edit the page to generate the link) but what about all the other sites out there with relevant content, they may not have your service in thier list of "bookmark this" services. Well, you could also create a very simple plugin or bookmarklet for you users that would allow them to add pages directly from a page they are viewing as well. And then they could also just copy the link and visit your site.

I have not ever seen this implemented and can't find a module (or proposal for one). If anyone else has ANY input it is very welcome.