You know I'm a freak about Google Reader, and one of the reasons I love it is the Share function. I have a few buddies with whom I exchange interesting posts — for those unfamiliar with it, you can share posts from the feeds that you subscribe to with people on your shared list on Reader. I love sharing so much that I was shocked when my friend told me I could share anything, from any site, whether or not you're subscribing to that feed (or if they don't offer a feed to subscribe to).
Say you run across a video on YouTube, and want all your buddies to see. From this Notes page, drag the "Note in Reader" bookmark to your browser, and then when you find that amazing kitten-in-a-box video, just click that Note in Reader bookmark, and the sharing box pops up as if you're on your Reader page.
To your friends, it will appear exactly the same as the posts from your feeds do.