We use this plugin a lot and are thankful for your work.
One suggestion: If I happen to be running the widget prior to ordering the links, and debug mode is on, the entire SQL query, to include my table names, if printed to the browser.
My specific complaint is the db prefix being printed to the browser. That seems excessive. I can find out what my tables names are very easily, and no one else should be able to, ever, under any circumstances.
My suggestion would be just run something less informative, or even better, prevent the error my creating the necessary db columns on plugin activation rather than upon ordering the links.
Thanks again for a very clever and useful plugin.