This is most about Mozilla Firefox but some of the tricks can also be done in Mozilla.
This is Mozilla and Firefox's advanced configuration tool. Type about:config in the Address bar and hit enter and the configuration options load in the main window, for easy editing this allows full control over how Mozilla works. Allowing you to change any setting that exists. A word of warning though I'd suggest using google to check what a setting does before changing it.
Similar to about:config and accessed the same way. Type about:plugins into the address bar and hit enter.
This lists all the plugins that are currently installed with the browser. It's of no real use except to tell you what types of special content your webbrowser can deal with.
Plugins and extensions
Firefox is designed to be easily extended allowing users to add extra features to it. With this in mind it has a strong plugin frame work and a large number of plugins have been developed for it allowing it to do quite a few cool things. These extensions can be found at this location. They allow Firefox todo all sorts of cool things such as, controlling it with Mouse gestures, blocking the annoying Flash ad's many sites use, block banner ad's, reload your previous session when you open the browser (ie any pages that you had not closed in tabs last time you quit it) and many other things.
Ones that I recommend are.
Flashblock Which replaces shockwave and Flash items with a small icon that can be clicked to view them. Really good for getting rid of the big flashing Flash/Shockwave ad's some sites use.
Adblock a plugin which hides or removes banner ad's from web pages when you view them.
The extensions can be configured, disabled or installed via "Tools > extensions" in Firefox 0.9 or greater. In the older versions they could be configured under one of the tabs in the Tool>Options dialog box.
Ad Blocking CSS
Another trick that can be done with Firefox is the use of an Ad blocking style sheet. One of which can be found here. By copying and pasting the code from that page into the example file, userContent-example.css, in Firefox's profile directory for which you can find the location of here and then renaming that file "userContent.css". Firefox will examine webpages you look at and remove an ad's it finds generally making the pages load abit faster and much easier to read.
Ad blocking host file
This is another some what more powerful way of block various types of ad's on the internet and has the effect of speeding up page loading and reducing the amount of bandwidth used. It prevents the ad's ever being sent to you. It works by telling the computer that it is the ad server. Your computer then asks it's self for the ads when a web page try's to load one and seeing it isn't really the ad server it can't find them and so the web browser just ignores them and loads the page.
This is done by creating whats called a host file which contains a list of internet address's such as www.blogspot.com and the ip address that web address points to eg 126.96.36.199. On most computers a host file is not present so the computer is forced to ask a DNS sever on the internet what IP address goes with what web address (url). If there is a host file though the computer checks that first and if it finds the url there then it doesn't ask the DNS server for the IP. Using the one in the host file instead. To block ad's what is done is a list of the special computers on the internet that host internet ad's is created and added to the host file. Then for each server the IP address 127.0.0.1 is set (a special address that always points to your own computer not to one on the internet).
Any way enough tech stuff. You can find an installer for Windows and instructions for MacOSX and Linux at this Site. http://www.everythingisnt.com/hosts.html
Any way that's enough junk for now from me, time to study :-(.