Juzer Burhani

The about:config page in Firefox allows you set preferences and tweak certain settings that are otherwise impossible to edit via the regular Firefox Options dialog. For instance, you can alter the default behavior of address bar, set your own domain guessing rules, change user-agent strings, and so much more.

The only problem is that about:config settings are too technical and packed in a geek interface which can be slightly intimidating to most Firefox users.
Luckily, there’re some excellent add-ins that add a visual interface (GUI) to about:config settings thus enabling anyone and everyone to "hack" Firefox without being a geek.

1. GUI Config - This lets you change the default behavior of mouse clicks, browser cache, download window alerts and a dozen other settings. You can hover the mouse over a setting to know in simple English how that change will affect the browser behavior.
GUI Config is accessible from Tools -> Advanced Settings.

2. Configuration Mania - While GUI Config gives you access to only a limited set of Firefox hidden settings, Configuration Mania supports a more comprehensive list though the help system is not that great.
The extension is nevertheless very powerful and combines features of several add-ins into one. You could change user-agents (to read magazines or WSJ), perform virus-scans after file downloads, disable security checks to install older extensions, etc.
Configuration Mania is accessible from Tools -> Configuration Mania.

• Better Gmail 2
  Version 0.5.2: Updates and fixes the Redesigned skin; Adds Hide Gmail chat script.
• Better Flickr
  Version 0.3: Adds Firefox 3 support, Rich Edit, Photo Page Enhancer, and Thumbnail Page Enhancer.
• Better GCal
  Version 0.3: Adds the Redesigned skin beta by Globex Designs.
• Better GReader
  Version 0.3: Adds Colorful List View; Updates the Minimalistic skin; Adds international domain support including google.co.uk, google.es, google.de, and others.
• Better Lifehacker
  Version 0.2: Adds HTML Helper and Nested comment replies.
• Better YouTube
  Version 0.4.3: Adds Firefox 3 compatibility; Fixes FlowPlayer (alternate, non-autoplaying player) and YouTube Theater view.

Another one for Gmail crazy people ...
Lifehacker has updated its Better Gmail 2 Firefox extension .. grab it here.
Download version 0.5.1 here.

Windows/Mac/Linux (Firefox): Site-finding service StumbleUpon has taken full advantage of Firefox 3's "Awesome Bar" by integrating its browser toolbar/extension with Firefox favorites. A new option in the latest version of the previously highlighted StumbleUpon add-on lets you download all the sites you've rated with a thumbs up/"I like it!" into your bookmarks, giving you as-you-type access to that last cool link you saw but can't quite remember. Your recent favorites and their tags are also stored in the browser's "Recent Bookmarks" and "Recent Tags" Smart Folders, helping your organize your idle-time browsing. StumbleUpon 3.23 is a free download, works wherever Firefox 3 does.

StumbleUpon 3.23

Windows/Mac/Linux: Firefox extension Xoopit turns Gmail into a robust, searchable media management tool for every piece of media that comes through your inbox. By indexing every attachment as well as every link to photos and videos from sites like Flickr, Picasa, and YouTube, Xoopit allows you to easily search for and find any picture or video and view it from directly inside Gmail. Imagine this: You're looking for a YouTube video that you were sent a link to recently, but you really don't know where to begin your search. With Xoopit installed, you can just click the Videos tab and you'll see this:

Finding that video becomes a lot easier at this point, but you can narrow down the search even further by sorting the results, filtering by sender, or searching for the words associated with the video (even if all the original email contained was a link).

Today, Xoopit has also integrated their media search with Gmail's search box so you can get media results when you search Gmail the regular way (see their demo video for more). Once you're viewing a video or picture in Gmail using Xoopit, you can even post it to Facebook or to your blog directly from Gmail (WordPress, Blogger, TypePad, and LiveJournal are all supported).

Overall, Xoopit sounds (and is) pretty great, but there is a catch, and it's kind of a big one: You need to be willing to turn over your Gmail password to Xoopit to allow them into your inbox to index all of your email. It would be excellent to see this sort of functionality incorporated directly into Gmail so you don't need to trust a third-party with your inbox. However, if you give it a try and are unhappy with Xoopit, you can email Xoopit support and have your account deleted.

Xoopit is free, works wherever Firefox does. They're currently in a private beta, but they've promised access to Lifehacker readers who follow the signup link below. As soon as you sign up, Xoopit will start indexing your media. You should start seeing indexed content in a few minutes, and all of the media in your inbox should be indexed in under 24 hours. If you give it a try, let's hear how you like it in the comments.

TableTools is a Firefox extension that lets you sort, filter and export tables from any web page. After installing the extension and restarting Firefox, find a web page that includes tables (this search might help) and right-click on a table to find a lot of interesting features:

* sort a column, depending on the type of elements (text, numbers, dates)
* filter the rows of a table by selecting elements from a drop-down or by entering your search terms, like in the screenshot below. You can even enter regular expression to filter more complex patterns. After typing the query, press Enter or click outside the active input box.
* export the entire table as tab-delimited text, HTML code or just the filtered rows


This might be helpful if you want to insert some partial data from a table in a document, a site or in Google Spreadsheets, which only supports filtering using a limited gadget. For Google Spreadsheets, choose the option to copy the rows as tab-delimited text.
Via Google Operating System