Webware has an interesting post with a video up about a very useful Firefox extension called Drag and DropZones. It lets you perform quick, gesture-based searches across a huge array of search engines, and execute commands you would normally use your keyboard for with quick gestures. I've been trying it out, and it looks like a definite time-saver. Here's a screenshot-based tour of how it works.
After installing Drag and DropZones and restarting Firefox, from the Tools menu, choose Drag&DropZones Settings. Then drag a search engine or context menu action from the left to a zone on the right to assign it. This zone is going to pop up as an available grid whenever you summon it, after you customize it. Assigning items to the grid looks like this:
 Below, after customizing my grid of search engines, I have selected the text Barack Obama at his Wikipedia entry. My next step will be to simply drag this text as though I am going to drop it somewhere else. The instant I do that, my Drag&DropZones grid shows up in a colored, transparent array showing various search engines that I can drop "Barack Obama" into. I am going to drag the text into the Google box that will pop up:
 The transparent pop-up grid with my chosen search engines is here:Â
Once I've dragged the text "Barack Obama" into the Google box on my Drag&DropZones pop-up grid, I've automatically launched a Google search, and this comes back:
 You can assign a huge number of search engines (and e-commerce sites such as eBay) to be part of your pop-up Drag&DropZones grid. Importantly, you can also assign context menu actions that you might normally pop up with your right mouse button to the grid. So if I am writing and I have assigned "Cut" and "Paste" to my zone, I can simply use the grid to execute those actions, without bothering with the right mouse button and menus. I recommend watching the video at Webware to get a feel for how the context menu items can go on your pop up grid.
This extension is worth a try, and can save you time entering text, using keyboard commands, and more. For many more Firefox extensions, including other tours like this one, see our Superguide.