• GMail,
• Twitter,
• Mac OS X Address Book database

Following is Mozilla’s release note:

The Contacts add-on integrates with local and web-based address books to bring all of a user’s contact data into a single database, which can then be used by browser extensions or web content.  The user must grant permission before any content can be used by a website, and can choose exactly which fields and personal records to disclose.

Download Experimental Contacts Addon

1. ECHOFON

Echofon was initially called Twitterfox. It is one of the most popular and useful addon since the poularity of twitter. Echofon adds a tiny status bar icon that notifies you when your friends post tweets. You can also view updates in a timeline and post your own tweets.

Noteable Features:
- Unread count in Firefox status bar.
- One-click access to Twitter window.
- Easily post links to current page in Firefox.
- Instant notification of new Tweets, within Firefox.
- Allows for multiple Twitter accounts
- Handles all the standard Twitter tasks such as direct messages and mentions.
- Syncs unread tweets with your iPhone when you use Echofon Pro for iPhone.
- auto pagination
- Combine sequence tweets

[Download here : download ]

2. REMINDER FOX

ReminderFox displays and manages lists of date-based reminders and ToDo’s. ReminderFox does not seek to be a full-fledged calendar. In fact, the target audience is anybody that simply wants to remember important dates (birthdays, anniversaries, bills, etc) without having to run a whole calendar application. ReminderFox makes sure you remember all of your important dates via easy-to-use lists, alerts, and alarm notifications.

[Download the addon here : download]

3. SEO QUAKE

Seoquake is a powerful tool ffor Firefox, aimed at helping web masters who deal with search engine optimization and internet promotion of web sites. Seoquakeallows user to obtain and investigate many important SEO parameters of the internet project under study on the fly.

It is one of the most useful tool for web developers  for analyzing optimization and promotion level of internet web-projects and all this bundled into the web browser itself. It actually consists of two functional parts – SEObar and SERP.

The features packed into this tool are powerful and better organised than in any of its compatriots. IT is one of the most recommended tool for SEO.

[Downlaod here : download]

4. READ IT LATER

This Firefox extension allows you to save pages of interest to read later. It eliminates cluttering of bookmarks with sites that are merely of a one-time interest.

Save pages to a reading list to read when you have time

• Offline Reading Mode – Read the items you’ve saved for later on the plane, train, or anywhere

• Access Anywhere – Manage your list in any browser, on any device. Your list is saved on readitlaterlist.com for web access. (Optional but enabled by default)

• RSS Feeds – View your list from anywhere with automatic rss feeds of your items

• Sync Between Computers – Sync your reading list with any number of computers, work or home

• After reading, bookmark pages on your preferred bookmarking service

• Click to Save Mode – Quickly batch a reading list just by clicking on interesting links

[Download here : download]

5. SCREENGRAB

Screen is an important tool for bloggers for capturing images of the rrquired window or region. It is used to replace the ‘Print Screen’ button on the keyboard which could capture the print of the screen and then edit it in paint or other softwares. With ScreenGrab one can save just a paragrap, an image, the full page or the frame. You can save the captured in jpg or png format.
Screengrab can also capture Flash and Java applets as long as you have Java installed.
To use it, just right-click a page to bring up the context menu and look at the options under “Screengrab”. It’s pretty self-explanatory!

[Download here : download ]

6. COLORZILLA

This tool as evident from the name itself deals with colour of the page. You can get a color reading from any point in your browser, quickly adjust this color and paste it into another program. You can Zoom the page you are viewing and measure distances between any two points on the page. The built-in palette browser allows choosing colors from pre-defined color sets and saving the most used colors in custom palettes. DOM spying features allow getting various information about DOM elements quickly and easily.

[Download here : download ]

7. GREASEMONKEY

I guess this addon would be known by most of the bloggers and it doesn’t need much introduction. Greasemonkey is a Firefox extension that allows you to customize the way webpages look and function. One can run different scripts on Greasemonkey and this expands the limits of usability to infinity. There are numerous scripts out there developed by different users and some of these scripts are very useful performing tough tasks in minimal resource usage. The world of Greasemonkey scripts is open and for you to explore. You are sure to find one that suits best to your needs.

[Download here: download ]

There are loads of great addons more which would prove to be useful for bloggers, but probably those in some other post.

Downloading facebook videos could be achieved by at least two means. One of the option is to download and use IDM ( Internet Download Manager) to download any facebook video you wish to. But  to avoid this means of using a third party software, one may use the new firefox addon to download any facebook video.

This Firefox addon is called – Facebook Video. This addon after being installed can be used to perform number of functions with the videos on Facebook. It adds four options under every video -  Download Video, Convert Video, Embed Video, and Customize Code option. So one can do a lot more than just downloading the video.

Clicking the Download Video will start downloading the video instantly in MP4 format. For converting the video it uses an online service called Zamzar where a user can convert the video to several formats and receive a link in an email to download the converted version. The customize code link opens a dialog to change the resolution of the embed code and/or select the auto-play option. Once the user selects “Update” the embed code in the box is changed to reflect the users preferences and the video will also be replaced so that they can view the immediate result of their changes The rest of the options can also be used effectively.

It was originally developed as a GreaseMonkey script but to make it further easy for users(to install), the developer has converted it into an add-on. It works on Firefox version 2.0 and newer including version 3.5

[Download the addon here : download ]