For some changes to be made, you need to edit configuration files manually in spite of using Firefox GUI.

There are three files you should know about:

userChrome.css
used to change the appearance of the browser

userContent.css
used to change the appearance of web pages

user.js
used to change various preferences

If you share your desktop, occassionally require a big set of Firefox extensions or use your browser for various, accurate applications, you should consider using multiple profiles.

• Download BugMeNot
• Homepage

Bypass compulsory registration - access websites that require you to register in order to view content.