You can set notifications to find out when your collaborators have modified your spreadsheets, and learn what sheets or cells they've modified. You can also choose how often you'd like to be notified.
DOF or Depth Of Field is a commonly used technique in photography where you can precisely focus only part of the face or object you are taking shot of. Let's recreate this using Photoshop.
If you want to put your video files online using HTML5 then it's recommended to have three different formats for a full browser support. Those formats are mp4, ogv and webm.
