This can load URI texts copied into the clipboard automatically. (You should not use this together with another application which observes the clipboard. This combination may cause troubles.)
And, when you open new tab, you can load the URI in the clipboard into the new tab instead of the default one.
If you see any problem, see FAQ at first. If there is no solution, post a report to the issue tracker on the GitHub please.
If you use Mozilla Suite or Netscape 7, see How to install and update? (contains important notes) This extension includes a self uninstaller. Please open the preferences panel Preferences > Advanced > Clipboard Observer, click the button Uninstall in the dialog. When you couldn't remove it completely, see How to uninstall by hand?