Some people call this an Extension or a Plugin but officially this is a Firefox Addon. Made by Damian Smith of Divergent Lines. There are many benefits of the tool, but for some of the task there are other plugins that are more useful that this but the feature that I like most is the Backlink check and Indexed Pages Check easily accessible with a right-click of the mouse.
Modified SEOPen for Firefox 3
I know some of you know how to simply modify the version required but some don’t. And for those that don’t but still love this extension plugin, you can download it here.
Yes this works, but this is not the official update of this plugin. I am also not the official maker of this plugin. No special functionality was added to this plugin. If ever some bugs come out (which I have never encountered) I am not responsible for whatever. When the official updates come out, replace this plugin with the official upgrade. But in the meantime, if you miss the add-on and need to use it now, then install this.