Courtesy of Michael Pisarek
The Datasheet view in SharePoint is one of the most used pieces of functionality in the platform for document management.
In essence it allows a user to edit multiple pieces of metadata in a nice Excel format. Frankly the idea that a user will upload a single document at a time and categorize it one-by-one was always laughable. In the majority of cases a user would perform an upload of multiple items and then categorize their contents as needed:
The datasheet view is the way to allow users to edit lots of metadata at once
But in previous versions of the product datasheet view had some serious limitations, mainly:
- No support for Managed Metadata columns which made it really difficult to use Managed Metadata in SharePoint 2010
- No support for browsers apart from Internet Explorer
- Just plain difficult to get it working since you needed an Active X Plugin to work
However all is not lost! In SharePoint 2013 one of the biggest improvements is the additional functionality and removal of limitations in datasheet view (now called ‘Quick Edit’). This means that users will be able to enter in metadata quickly and easily and we all know why that is so important 
So what are the big improvements? Read more
Jim Ehrenberg (SharePoint Pros, Inc.) 