Got some feedback on the first screencast already - some good and some bad. The good was that a viewer learned something that was not even on the topic of stacks and albums. The bad was that I should buy a better microphone. I will - I promise but first let's see if these things prove to be helpful.
I just wanted to share a tidbit from the first screencast that someone found very helpful. Now that I think of it I do see the question of how to apply adjustments to multiple images simultaneously come up on the Apple support forums a lot. I want to generalize adjustments to mean metadata - image adjustments - keywords - whatever.
Most people conclude that the "primary only" button is somehow broken in Aperture because adjustments or changes they apply only affect the primary in any group of selected images. Well it's not. There is a pretty simple rule to remember about how Aperture treats any modifications that you make to a group of images. Here it is:
If you use any of the inspectors to change the image - the metadata inspector, the adjustment inspector - in either the sidebar or the HUD those changes will only be applied to the primary - not the entire selection. If you use pretty much anything else like the menus, shortcut keys, or dragging a keyword from the keyword HUD to a group of selected images the changes will be applied to all the images unless the primary only button is active. Try it.
Of course you can always use lift and stamp as well. Here is a dissertation on the ups and downs of lift and stamp (forgive the pun)