How to set homepage for new tabs in Mozilla Firefox?

To permanently set new tabs to open on your homepage (or any web page you like), do the following:

1. Type "about:config" in the navigation pane.
2. A message will appear, informing you that, you could really screw something up if you don't know what you're doing. Click "I'll be careful. I promise".
3. Search for "browser.newtab.url".
4. Double click on it, and change the value to whatever web page you want new tabs to default to (i.e. http://www....)
5. Click OK and you're done!