Adding Blog Posts to Google Reader Shared Items without Subscribing

I've been addicted to Google Reader for about a year now.  It's completely changed the way I consume information, and I absolutely love it.

I've recently decided to give the "shared items" feature of Google Reader a try, and I've added a widget to my blog that displays my shared items.

But here's a thing that I noticed almost immediately after starting this journey: I can't add items to my "shared items" for blogs that I'm not subscribed to.  This is a major problem.

Here's an example.  Let's say I'm reading the latest Coding Horror post inside Google Reader, and Jeff links to an interesting post by Bruce Eckel.

I really like Bruce's post and I'd like to share it right along with my other "shared items".  But, since I'm not subscribed to Bruce's blog, and I really don't want to subscribe to it just to share a single post, I'm stuck!

While seeking possible solutions to this problem, I ran across this post (cached from Google).  Some of the workarounds listed in the comments were interesting, but I couldn't help but wonder if my beloved Firefox could offer a solution.

Here's what I'm thinking: could it be possible to cook up a Firefox extension that would automatically (and silently) subscribe to a feed, add the relevant post to my "shared items", and then immediately unsubscribe all in one glorious motion?

It's such a dirty hack, I know, but that's what makes it interesting.  Could be a fun side project.  I haven't the slightest clue how to develop Firefox extensions, but this could be an opportunity to learn.