The current UI of the extension is really bad. It is:
- Obtrusive (lying just below the heading)
- Confusing: Since the url is not accompanied by any indication that this is the url for the current page, half the people (those who don't bother clicking it) probably have no idea what it is for.
- Clickable: I'm not sure if having a clickable link is needed, since the objective of having a short url is to be able to copy-paste it somewhere.
I'd suggest that the url be moved somewhere more unobtrusive, and be presented with a heading/info (similar to what other sites use, such as "Link to this page"). One way could be such a tag (like "Link to this page") displayed somewhere prominently, clicking on which brings up a dialog box (jquery.ui.dialog maybe?) with the url selected for copying (along with a copy button, maybe?). I don't think there is a need for the url to be permanently displayed on the page.
PS:I don't see why we need the short url displayed at two places (in the sidebar as well as below the heading).