wrote the same thing when they first released social reader (it has been here on HN):

http://github.com/nikcub/frictionless

the problem is that they change the HTML elements every few days and it is a pain to keep up with it. I am in the middle of rewriting frictionless to use an external ruleset which will be updated, not requiring the extension to be updated.

you can see what we go through to get this to work consistently across loggedin/loggedout users, all the different apps (what you do wont work for all apps) and all the different use cases:

https://github.com/nikcub/frictionless/blob/master/webkit/fr...

(we also anonymize referral and click data)

Edit: to add, i'd be more than happy to merge the efforts and we are definitely seeking contributors. would rather one extension that works all the time than two that don't. we have already put in a lot of time keeping this extension up-to-date since launch with all the changes and updates made by the social readers.