What is a GEDCOM File?

There was some chatter at our recent genealogy social about GEDCOM files, what they were, why they were needed, what does one do with it, etc.  For those of you who are interested in learning more about the tech side of genealogy, please see this post in "RootsBid" giving a detailed explanation. While you are there, you might want to wander around and check out the website.  It is a place where genealogists can bid on doing work for other genealogists!  You can post your project and/or bid on work you can do for someone else.