Mouseless for Firefox updates with better support for web apps
The latest version offers improved support for dynamic web apps like GMail and Facebook. The number of "clickable" links has also been greatly increased and works amazingly well with complicated pages. On the Blogsmith post creation page where I'm writing this, for example, I've got 179 Mouseless links.
To "click" a link, just hold down your control key and type its number. Mouseless is smart enough to wait for additional digits if they might exist: if you've got a 110 available, it will give you time to enter a third number after 11. If not, the link is opened immediately.
You can also use Mouseless to create customizable navigation hotkeys. It's one of the best addons I haven't been using, and is definitely a productivity booster for anyone who uses a lot of web-based applications.