Useful Firefox add-on TwitterBar is now available for Chrome with almost all features and functionality of Firefox version.

Here is a cool trick to change the background color and font color of address bar in Firefox.

Futz.me is a very unique and useful tool.

URL bar search is another handy Firefox add-on which makes searching easy with multiple search engines.

If you love customizing Firefox in different ways, here is a new Firefox add-on for you which simply replaces the long URL in the address bar with the title of current page.

Source code of any webpage can be viewed using usual way of hitting CTRL + U or from View Menu of browser. But, you need to visit that webpage first.
Alternatively, you can try various source code analyzer for viewing source code of different websites. There are several firefox add-on as well.