I will show you how to enable desktop notifications, so you will notice a new email, even if you are not in the window where you have your Gmail account open.
If you are afraid of being hacked or someone else using your Facebook account you can enable option that will send you an email or text message in case your account has been accessed from a device that you never used before.
Sometimes you don't want your Mac OS X Mountain Lion powered computer to go to sleep, here's a nice little trick how to temporary prevent a Mac from going into a sleep mode.
