Rated 4 out of 5 stars

* Despite what the description says, the author's contact page does not work. I have tried it repeatedly to no avail -- it just returns me to the main page.
* In version 1.3.9 in Firefox 4, the status bar icon's context menu has no background color (i.e. it's transparent), making it impossible to see the menu text. This problem has persisted for quite some time and it would be nice if it were fixed at some point.
* The extension doesn't take advantage of the Firefox 4 add-on bar (no icon is added to the Customize Toolbar window), meaning the Organize Status Bar extension is required to arrange its status icon.
* The two quirks and no way to request support aside, Linkification remains an excellent and versatile tool for conveniently opening plain text links.