Type ‘about:memory’ in the address bar and press Enter in order to get information about how much memory Firefox has reserved and how much memory is the browser actually using at the moment. You can get cache information on the screen with the command about:cache.

You will come to know where Firefox buffers its data (RAM, hard disk and network), how memory space is utilized on the whole and how much memory is still unused. If you want to know this in detail, you need to also know which entries are saved. They are listed as links on request (click the link).

In version 4, many add-ons are disabled by default because their compatibility has not been tested and released for version 4. Although suitable updates are offered for many plugin, there are other add-ons that are functional with Firefox 4 in several cases. In order to be able to see these, you must disable the compatibility check.

This can be done with the help of an advanced configuration setting. For this, type ‘about:config’ in the address bar and press Enter. Confirm the displayed warning by clicking ‘l’ll be careful, I promise!’. Now right click in the window and select the context command ‘New->Boolean’. Then enter the term ‘extensions. Check compatibility 4.0’ and press Enter. In the next dialog, select the setting ‘false’ and click ‘OK’.

Then close the tab with the configuration. In future, all the old add-ons can now be formally installed. The specified setting does not ensure compatibility but bypasses the compatibility check. It is thus possible that the individual unchecked add-ons do not function correctly with Firefox 4. In such a case, you have no option but to wait for an update by the provider.

NOTE: The exact team of the additional entry depends on the Firefox version used which can be seen at the end of the name. The specified value refers to the end version. You then alternatively or additionally need the entry ‘extensions Check compatibility 4.0b’ for the Beta version to which you assign the value ‘false’.

A better option is to add back the RSS button to the navigation bar. To do so, right click on the Firefox button, and under Options click on “Toolbar Layout”, this will open dialog that has a number of widgets that can be added to the add-on bar or the navigation bar. There will be a button labeled “Subscribe”. Drag this to the add-on bar, navigation bar or even the tab bar and menu bar!.

You can now click on this button to get the same functionality as the RSS button in the Firefox 3 address bar offered.

* Go to the about:config page by entering it in your location bar and agreeing with the waring.
* Enter  inspector in the filter area.
* Now double-click on the devtools.inspector.enabled entry.
* Restart Firefox.

Now your will find a new entry “inspect” under the “Web Developer”. sub-menu in the Firefox button.You can also find it in the tools menu if you have the menu enabled. or you can toggle it with [ctrl]+[shift]+[i].

The feature wasn’t completed and is not enabled by default. It works well enough but can be quite buggy, so beware before enabling it.

If you want to get back the old status bar that displayed connection status and other such information, you can do so by installing the Status-4-Evar add-on. Not only does  this add-on bring back the old status bar, it adds a number of nice features that were removed / written for Firefox. but never made it in . For Example you can display the loading progress as a line under, over, or inside the address bar.

Similarly, you can get back the old Firefox menu by clicking on “Menu bar” in the same menu.

Now you have a Firefox 3 like User Interface, except that there is no status bar. If you just need the status bar of add-on icons. then there is a simple way to toggle between displaying and hiding the add-on bar using the shortcut [ctrl]+ / .

A New Look:

Current trends dictate a smaller UI footprint, as websites takeover many of the functions usually reserved for browsers. Firefox 4 optimizes UI space for the content that need to be displayed.

•    No Menus: Firefox has the new menu that has two columns with the most popular browser options.

•    Tabs on Top: Tabs-on-top are a much better paradigm than the older tabs below the address bar system as they clarify that the address bar and browser controls apply to the current tab rather than the browser as a whole.

•    No Status Bar: Mozilla has gone for Google Chrome like transient status bar. And a new add-on-bar for icons.

•    New add-on Manager: The add-on manager has seen a significant overhaul, and not just in looks, but in features as well. The new UI lets you search for locally installed add-ons in addition to add-ons from Mozilla’s database. Add-ons show much more detail now, and one can even click on the “more” button to see further detail about the add-on.

New Features:

Firfox 4 adds a number of core features earlier available only via add-ons.

•    Firefox Sync: This is now an in-built feature. It allows synchronizing bookmarks, passwords, preference, history, and tabs. Setting up sync has also been further simplified- you no longer need to remember two passwords.

•    Panorama: Firfox Panorama sets the browser apart from  all others. Panorama introduces an entirely new way of managing tabs by visually arranging tabs in groups using a thumbnail view and lets you focus on one group of web sites at a time.

•    App Tabs: This feature is pretty much the same as pinned tabs on Chrome and Opera. Tabs can be collapsed to showing just the icon of the website, thus saving space in the titlebar.

•    Restartless add-ons: Firefox’s extensibility comes at the price add-ons need restarting the browser. Well no more! Firfox 4 lets developers create add-ons in a way that enables installation without requiring restart.

•    Tab Switching from location bar: When you start typing in the location bar, Firefox now allows you to switch to existing tabs that match your entry.

•    Do not Track: Firefox now includes an option that lets you opt out of being tracked by websites. However this features is of limited use until its is respected by such parties.

•    Multi-touch support: It your’re one of the few using Windows 7 with  a multi- touch input device, you will now be able to use gestures with Firefox.

Firebox 4 will also be the last major change in the history of the browser.

Firefox free internet browser was developed from the begging to allow fast webpage loading, internet browsing and fast downloads.

Firefox getting excites more reviews from the likes of USA Today, PC Magazine, PC World and more world top Magazines. Firefox also includes a download manager that will allow you to pause and resume downloads.

Firefox definitely more secure than Internet Explorer, Still Microsoft’s security program manager runs Firefox!

Simple task to Install Firefox:

1.    Browse to http://www.mozilla.com/en-US/firefox/personal.html

2.    Click the download link appropriate for the OS on which your PC will be running Firefox-  Ie.Windows, Mac OS X or Linux,

3.    Save the file to your PC desktop.

4.    Double-click on the file you just downloaded to start the installation wizard.

5.    Click “Next” on each step of the wizard until the program is installation.

6.    Start up Firefox, and  browse

7.    If you like, you can set Firefox to be your default browser, instead of Internet Explorer.