You got a .rar file and you don't how to open it, some one asked you to send him "a rar file" or you just need a good archiving software? Download and install WinRAR.
You are preparing a world wide event in your city and you want to be sure that every person around the world will know the exact time in their city. You will find out how in this tutorial.
As from November 11th Google will launch a so called Shared Endorsements for products or services which will allow them to use your picture when displaying ads to your friends.