The MediaBugs widget
The MediaBugs widget lets any website add a button to any page so your users and readers can easily report errors and problems they find.
Users can file these reports without registering at MediaBugs, but we encourage them to register after they file a report so we can provide them with updates about the progress of their "bugs."
You can see a demo of the widget in action on Scott Rosenberg's Wordyard blog, where every post comes with a "report an error" link. More examples coming soon!
For technical details and to get the working code for our widget, see our Developers' Guide.
For WordPress users we've also got an easy-to-install WordPress plugin.