One Newbie's Understanding:
For the last few days I have been trying to get my head around the Omega 3.x theme's grid layout settings. This article attempts to describe my understanding of these settings. I am not a Drupal or Omega theme expert by any means, but someday I would like to become one and I believe that writing these articles helps me achieve that goal. This confession should also be interpreted as a disclaimer or warning to those reading this. I probably have misunderstood a thing or two, and in any event, the Omega 3.x theme is in Beta 1 as of this writing and is changing often, so use this information with caution.
Enabling the Responsive Grid
Near the very top of the Grid Settings section is a check box to "Enable the responsive grid". This is the heart of the Omega theme.