Linux with Firefox only: Free Firefox extension Tomfox does exactly what a fan of the Tomboy note system might think. Adding a "Create Tomboy note" option to Firefox's right-click menu, it creates a new note from selected text. Even better, it puts the title of the web page at the top, and a link to the page at the bottom of your new note, helping you remember just where you grabbed that text from. Tomfox is a free download, works with Linux/Firefox and the Tomboy note program.

Windows only: The free Orca Browser is a web browser based on the Firefox 3 core with the same speed and features of Firefox in addition to a handful of extra features. Those extra features include a built-in ad blocker, flash blocker, auto form-filler, and perhaps most useful, an online storage account that syncs your bookmarks, auto-form information, and more with an online account. Orca is made by the same folks who developed the freeware Avant Browser, which is based on Internet Explorer with an emphasis on speed and improved features.

Firefox with Greasemonkey: The Google Reader for Wider Screens Greasemonkey script uses all the horizontal space available in GReader for better viewing on wide monitors. Install the script to take advantage of a wide browser window and scroll up and down less than you have to. The Google Reader for wider screens user script is a free download for Firefox with the Greasemonkey extension installed. Thanks, Andy!

All platforms with Firefox: You already know how to Google a word's definition, but to find out what a term means without having to switch tabs you need WikiLook. The WikiLook Firefox extension adds very useful functionality to the browser: With Wikilook installed, when you come across a word you don't know, press and hold the Shift key and move your mouse pointer over it. WikiLook will load the definition (pulled from Wiktionary) in a green tooltip on the spot (as shown). WikiLook is a free download for Firefox, and should be #11 on our top 10 online language tools for word nerds.

Windows/Mac/Linux (Firefox): Free Firefox extension UnMHT gives Firefox the same abilities to save a complete web page as one file—sound, pictures, video, and all—as Internet Explorer and Opera already have, but with a multi-tab bonus. Once installed, Firefox can open any of the MIME HTML (.mht) files saved by another browser, but UnMHT also adds a "Save all tabs as MHT" option, letting you store an entire browsing session as multiple MHT files with two clicks. Great for saving a work session for later restoration, or saving what you're looking at now for complete offline reading later. UnMHT is a free download, works wherever Firefox does.

Windows/Mac/Linux (Firefox): AideRSS, an RSS feed popularity filter that Adam had a few bones to pick with, has released a free Firefox extension that integrates its popularity rankings into Google Reader. AideRSS says it uses the number of comments, Google backlinks, bookmarks on social sites like Digg, reddit, and del.icio.us, and more data to determine a PostRank, which it plugs next to each feed item and offers as a drop-down filter. While it's obviously going to bias your reading against fresher posts that haven't had time to make their mark, it might be helpful to anyone trying to cut down on RSS clutter. For their next version, let's hope for an options dialogue to remove that PostRank number from every single post, as the filtering bar may be more useful to most users. AideRSS is a free download, works wherever Firefox does.

Firefox with Greasemonkey only: The Google Contacts Autocomplete user script adds a drop-down of your Gmail contacts on any web-based email form where you'd enter an address. You must be signed into your Gmail account for the script to work; once it's installed, just start typing into an email text field to get search-as-you-type results from your Gmail address book. The first day or so it was installed, the script did nothing for me—then it magically started working (see screenshot)—so your mileage may vary. When it is working, this is a nifty way to access your contacts quickly and easily. The Google Contacts Autocomplete user script is a free download and requires Firefox with Greasemonkey. Thanks, Matt!

Firefox only (Windows/Mac/Linux): Firefox extension Panic provides a simple keyboard shortcut to instantly close all of your current tabs while opening a new, more appropriate one. So let's say you're at a workplace that supports reading Lifehacker (you are boosting your productivity, after all). You could set Lifehacker as your panic URL, then start looking for your boss's birthday present on Amazon. (You are so nice!) When your boss turns the corner, just hit the customisable keyboard shortcut to close your active windows and fire up your panic URL. Of course, Panic's boss key would work just as well for less noble purposes, and it works fast. Panic is free, works wherever Firefox does. For other Panic alternatives, check out previously mentioned apps like the Magic Boss Key, Windows Hidie, and workFriendly.

Firefox only: Our favourite bookmark syncing Firefox extension, Foxmarks, can now sync select sets of bookmarks to certain computers you set up, like at home or at the office. To get started with selective syncing in Foxmarks, log onto My Foxmarks with your usual login, and in the Tools menu, choose "Manage Sync Profiles." Assign bookmarks to your sync profiles—like family bookmarks to the Home profile and office links to the Work profile. Then, on each computer you use Foxmarks on, make sure you've got the latest version 2.1.0.12 installed in Firefox. In the settings dialog, on the Profiles tab, choose which profile that browser instance should sync. While Foxmarks doesn't sync anything else of your Firefox user profile other than bookmarks—the way Google Sync used to, and Mozilla Weave does—this is still a really useful feature for compartmentalising your bookmarks and making sure sensitive or personal links only show up on the computers you want them on.

Firefox only: Save time shopping at Amazon.com with the new Better Amazon Firefox extension, which adds helpful tweaks and features to Amazon's pages. Better Amazon highlights which products the big A offers Super Saver free shipping for in search results, automatically enlarges product images, shortens Amazon URLs for easy emailing, and collapses superfluous junk on the page when you just need to get simple tasks done. After the jump, download Better Amazon and get your (stateside) online shopping done more efficiently.