If you want to, you can think of a document library as a Windows file folder, but better. Like folders, libraries act as document storage, but they also store the document's metadata or version history (more about this a little later) that folders do not. Also, folders lend themselves to user personalization in that they may stay on a user's drive or be labeled differently from another user's folder, which leads to inefficiency. You don't encounter this in libraries, which acts as central store, shared across an organization. SharePoint also offers collaboration features that go well beyond the traditional file-sharing techniques that you may have used in the past. Because SharePoint stores lists and libraries in a database rather than the file system, it is arguably more secure, more efficient, and enables more sophisticated document workflow and content management scenarios.
You should remember the following as you work with libraries:
Storage Types: You can store a variety of file types, including presentations, images, archives, or spreadsheets. You can store virtually any file type in a SharePoint library as long as the file type has not been added to the Blocked File Types listing.
Managing Blocked File Types
You can view the listing of blocked file types for your SharePoint environment by visiting the Operations tab of your SharePoint Central Administration site for your server farm. Once there, you can find a link to view blocked ...