So, AddThis just added a cool feature that attempts to track when people share URL's via cutting and pasting the address from the browser.
It appears to do so by adding a URL fragment on the end of the URL, hoping that the person sharing will cut and paste the entire thing. That seems like a reasonable assumption to me.
Unless I misunderstand, it seems like it will add a fragment to every URL (since it's trying to track all of 'em). Probably not a huge issue for the search engines when they crawl, as they'll, hopefully, discard the fragment, or discard the JS that appends the fragment.
But what about backlinks? Natural backlinks that someone might post to say, their blog, by doing exactly what AddThis is attempting to track - cutting and pasting the link.
What are people's thoughts on what will happen when this occurs, and the search engines crawl that link, fragment included?