Select database queries with Inner, Left and Right Join represent an important part of SQL syntax and come in very handy when you want to make more advanced queries.
Nice little program that enables you to close all your opened applications and windows with one single click. It works in Windows XP and Windows 7 and doesn't need installing.
Most of the annotations popping up while you are watching YouTube videos are really annoying, but there is a really simple on-click way to get rid of them.
If you are on a certain data plan on your mobile provider, and don't want to exceed it, you can set data usage warning and a limit which can help you save some of your money.