Blender is of course a 3D package but it is possible to use it to create 2D animations. So why would you want to? there are some good reasons.

Going from 3D to 2D
Frequently in Blender we view a 3D scene using an orthographic projection. Orthographic projections eliminate perspective so objects are the same size whether are near or far from the viewer. By setting the camera to orthographic you effectively turn Blender into a 2D system.

Has Blender got the tools for 2D animation?
3D animation is about the movement of 3D models. 2D animation is about the movement of 2D graphics. A 2D animation package usually comes with a set of graphics creation and modification tools.
Blenders modelling tools can be used for creating 2D graphics but obviously they were not designed for the purpose.
An image produced in a graphics package can be mapped to a plane in Blender. If the image is in the PNG format it can have a transparent background.

What are the reasons for using Blender?
There are not many free, powerful 2D animation packages but there are several free powerful graphics packages. Images can be made the graphics packages and then animated using Blender’s animation and video editing systems. But there are better reasons than this.
It is very easy integrate 2D graphics and 3D models and so give a whole new range of tools and facilities to 2D animation creation, the possibilities are limitless!

Making a Ball Bounce Around the Screen

Example 2D Animated Movie

How to make ‘A Car Drives Past Things’ Part 1

How to make ‘A Car Drives Past Things’ Part 2

For tutorials on how to add music, sound effects, titles and credits go to the making a short movie page

Easing Modes, Ease In & Ease Out for a Ball and a Car