Firefox Extensions for Experienced Users
Updated August 8th, 2007.
Previously, I show-cased some Absolutely Necessary Firefox Extensions that no user should be without. They were simple, functional, and suitable for even novice users.
This list is for more experienced Firefox users. The extensions here are functional, but are more complex and may involve some user interaction. While a relative novice to Firefox should have few problems using these if they are reasonably familiar with computers and browsing in the first place, dear Great Granny who is convinced that she will literally blow up the computer if she hits the wrong key might find some of these challenging. ;)
We are also moving into the realm of individual taste. You may find some of these extensions more useful than others, depending on your browsing habits.
Those extensions that I personally find invaluable will be marked with: Favorite!

1. Bookmark Management - Manage your bookmarks:
• Update Bookmark  - Favorite! - Allows bookmark properties to be set to the current page's properties or to clipboard text quickly via the context menu. This is great for keeping your bookmarks up to date.
  
2. Browser Appearance Tweaks and Themes - some extensions for altering particular bits of the browser appearance, as well as some highly functional themes:
• Autohide - Favorite! - True Fullscreen! Hides everything except the scroll bars. When you move your mouse to the top of the screen, the toolbar glides down. Perfect for the dedicated web-surfer!
• Compact Menu 2 - Favorite! - Combines all the menus from the Menu bar into one cascading menu which may be accessed via a single button on the toolbar. This is especially useful for those who like to browser at True Fullscreen all the time - we can now access all the menu options without needing to leave fullscreen mode.
  
• Find Close On Right - Move the find bar close button to the right. One of the little things that bugs me is the fact that the button to close the find bar is located on the left side of the browser window. Close buttons belong on the right! This little extension fixes the problem and puts the close button where it should be, on the right. Of course, you could just get into the habit of pressing "ESC" to close the find bar, and then you won't care where the close button is.
  
• Fission - Progress bar in the address bar (Safari style). This combines the progress bar and address bar, adding a neat visual affect and allowing you to save screen space. If you need to see a progress bar, this is the extension for you. Personally, I find the little throbbers on every tab work fine for me.
  
• Menu Editor - Favorite! - Customize application menus. If you have a lot of extensions, your right-click context menu is probably getting a bit crowded. This lets you hide all the menu items you don't need, so they won't show up on the context menu. You can also rearrange the order of items so it makes more sense for your browsing habits.
• New Tab Button on Tab Bar - Adds a new tab button to the tab bar. If it seems more natural to have the new tab button on the tabbar itself instead of on the navigation toolbar, this extension makes it happen. However, in Firefox 1.5, you don't really need a "New Tab" button at all, as a new tab can be invoked with the hotkey Ctrl+T, or by double-clicking on an empty area of the tab-bar, or by right-clicking on the tabbar and choosing "New Tab". You can open a text link in a new tab by simply selecting and dragging the URL to an empty area on the tabbar. For new Firefox users, though, having a visible "New Tab" button can help remind them of the feature. Also, you can drag text URLs to the "New Tab" button to automatically open them in a new tab.
  
• No Go Buttons - Favorite! - Gets rid of the Go buttons for the address box and the search box in Firefox 2.0 and above.
  
• Searchbar Autosizer  - Expand the searchbox as you type. This allows you to make the search box really small when there is no text in it, which saves toolbar space. The search box also expands as you type in it.
• Simpler Blue  - A simple theme using easy-to-use icons - now in blue. This is my favorite theme. Simple, elegant, easy to see, with no incompatibilities that I have noticed.
  
3. Extension Management - Manage Extensions:
• MR Tech Local Install - Favorite! - Local Install power tools for all users. This is great extension that lets you better manage your extensions. Populate a list of your extensions. Arrange your extension alphabetically. Stop checking for updates to particular extensions. Easily install extensions from your hard drive. Override the Extension version compatibility check - especially useful if you are using nightly builds. Force Compatibility after an upgrade when Firefox automatically disables incompatible extensions. You can also do the same for your themes. Tons of nifty tricks and tweaks. Add a Restart Firefox button to the toolbar. Etc.
  
4. Forms, Blogging, Editing, Email - Extensions to add email, editing & blogging features:
• Autofill - Favorite! - Fill out forms with just one click, supports multiple profiles/identities. Very effective and useful. Note: At the moment, this extension is still in Mozilla's Sandbox area (where extensions are tested before they are released to the public), so you will need to login to your Mozilla Add-ons account before you can access it. If you don't have an account, you will be given the option to make one. Is it worth the extra work? Absolutely! This is the best form filler I have ever used, and I have tried them all at least once.
  
• Better Gmail - Favorite! - A compilation of Greasemonkey scripts to make Gmail's online interface more useful and efficient. Greasemonkey is NOT needed to use this extension, but a Gmail account IS neccessary.
  
• Deepest Sender - Favorite! - Post to blogs directly from SeaMonkey/Firefox. If you blog, especially on livejournal, this extension is for you. A wonderful, feature-rich blogging client right in Firefox. It's easy to use with a WYSIWYG interface. I'm using it to make this post. Thanks to this extension, I have finally been able to start and maintain a private journal, something I have never been successful with before. I also make more posts on my public journal and am more likely to share things I find online, thanks to the ease of posting with Deepest Sender.
• Gmail Manager - Favorite! - Gmail accounts management and new mail notifications. This lets you manage multiple Gmail accounts right from your toolbar or statusbar. This is the best mail-notifier I have tried.
  
5. RSS Feeds - Adds advanced RSS Features:
• Sage - Favorite! - A lightweight RSS and Atom feed aggregator.  I love this extension. Makes LiveBookmarks make sense. You can use this to watch and read all your RSS and Atom feeds in user-friendly interface. This extension is what introduced me to the wonderful world of RSS.
  
• Feedview - Make your news feeds nicer to read. I wavered a bit about which list this belongs on. Actually, it's a really nice and simple feature that should be built right into Firefox, so I guess it's suited to either list. Basically this cleans up the default view when you open an RSS feed. A nice little feature that adds that "extra touch" to any Firefox install.
  
6. Searching Customizations - Advanced Searching features:
   
• Coogle - Favorite! - A tiny extension that highlights the search terms on pages you follow from a Google search results page.  Really handy.
  
• CustomizeGoogle - Favorite! - Enhance Google search results and remove ads and spam. This really cleans up the Google search results and adds some nice enhancements. Adds links that let you try your search on other sites, removes text ads, allows you to block results from particular sites, lets you bypass the copyright notice/frame on Image search, and much more. The main reason that this is on this list and not the novice list is because there are A LOT of preferences to tweak in order to really take advantage of this. Don't worry, they are all laid out in a nice preferences panel, but some of the choices are a little complex. The homepage for this extension does offer a tutorial movie, check it out if you feel intimidated by all the choices. Personally, I love this extension and wouldn't be without it.
7. Sidebar Functionality - With these extensions, using your sidebar becomes a joy.
• Ez Sidebar - Favorite! - Allows to take web pages into sidebar panels like Mozilla(Seamonkey), and provides undockable Sidebar. But that's not all. With this, you can access all your sidebars through the sidebar interface. No longer do you need a button on the toolbar for every sidebar, because this extension gathers them all under one button with a drop-down menu. And when you have the sidebar open, just go to the panels button at the top of the sidebar to switch between sidebars (bookmarks, history, sage, extension manager, etc.). I prefer this extension to All-in-One Sidebar, another popular sidebar manager, because it is simpler and more user-friendly.
• Optimoz Tweaks - Favorite! - Sidebar autohide and other user interface tweaks. When used in conjunction with EZ Sidebar (above) this eliminates the need for any sidebar buttons on the toolbar. The main feature of this extension is the auto-hide/show feature. When you put your mouse on the left edge of the browser window, the sidebar appears. You can configure the auto-hide function so that the sidebar either hides when you move the mouse back over the browser content, or when you move the mouse back to the left edge of the browser. I prefer the second option, as it allows you to have more control over when the sidebar hides. Using this with EZ Sidebar means that you will be able to have access to all sidebar panels quickly with no need for toolbar buttons.
8. Misc Other - Handy Extensions that don't fit anywhere else:
• Drag de Go - Favorite! - Allows you to preform several drag-and-drop functions with Urls, links, files, images, etc.
• LastTab - Favorite! - Allows tab-flipping and customized settings for tab focus order.
  
• Open Source in Tab - Opens the page's source file in a new tab. If you look at the source code for web pages very often, this extension can help you avoid having lots of windows open.
• Story Monitor - Favorite! - Monitors stories on online fan fiction archives for new chapters. For us Fan Fiction Fans, this extension is a great way to keep track of your favorite stories. The interface is not perfect, but it works. 
• Update Scanner - Favorite! - Allows you to monitor web pages for changes. Perfect for watching fan fiction archive sites that don't use RSS feeds.
  

Want to see what extensions I'm using right now? Click here.