I had never heard of these programs until trying to find one that will work with something I just downloaded. What exactly is a database and why do I need one for some programs? Are these databases files on my machine, or do they require Internet connection? If so, where are they stored? What is the file extension of databases? I mean I know what the word "database" means, but I don't understand how it works in this instance or why it is required right now. Don't most programs just save all their "data" in a file that can be opened by that program? (.xls, .doc, .txt, .....). What's the difference here?