Something I have been glossing over in my End User SharePoint class has been working with the Lookup Column option in a List or Library. It has taken a while for me to figure out a functional use for this feature from a military perspective.
Basically, the Lookup Column acts like an automatically updating Menu List, based on a column you choose from a DIFFERENT list or library.
I created a powerpoint on
My SharePoint Site that shows how to use this feature.
There are a couple of different reasons to use the Lookup Column. The first is to separate permissions. Perhaps one shop or section is resposible for adding points of contact (like the S-1), and other is responsible for uploading LOIs (Letter of Instructions--like the S-3).
By using the Lookup Column, you can create a Custom List called POC that the S-1 has contribute permissions over so they can maintain/update contact info, and the S-3 can upload their files and have an automatic list of possible Points of Contact from the command added to the 'metadata' for their uploaded file.
Another reason to use the Lookup Column is to save typing. If you find that you use the same menu over and over again for your SharePoint lists/libraries (like a column called Section that lists all the command sections...or better yet, a RANK column--it is really annoying to type every possible rank without even talking about the Navy rank structure).
In these scenarios, you can create ONE custom list with the items you need (like Section or Rank) and enter all the options into that list. From there, any time you want to use those options create a Lookup Column and link to it.
One drawback, you have to create the Lookup Column in the Site you want to use it in. That means that if you create it on your home page, you will not have it available for sub-sites without doing some heavy programming work arounds.
Again, if you want to see the Lookup Columns Step-by-Step, go to
http://usmc-sharepoint.com and use the login/password of Marine/password. From there go to SharePoint Support.
Hope this helps!