we're going to be upgrading from LR5 to CC, and we'll probably have to re-image the computers, so if you do not back your catalogs up, you may lose all your pictures.
Click on the image for instructions on how to export you catalog. Make sure you go through all of you images and cull the bad ones before you do this; this can drastically reduce the overall catalog size and make your life a lot easier.
Lots of great reading in the newest edition of the online publication.
Here's a pretty good collection of terms you should be familiarizing yourself with.
Everyone should watch this video from The Slanted Lens on how light behaves.