I think this is an extremely interesting development, and worth mentioning here for those who are interested in animation tools. The sculpt tools to affect drawings look great to animate with. All the strokes shown are vector based.
More info for those interested:
First, in Blender 2.77 new sculpt tools for the Grease Pencil will be introduced (the pre-release candidate is available for download here: http://wiki.blender.org/index.php/De...s/2.77/GPencil), which allow the user to sculpt drawings. It is a great new feature, making it a doddle to add squash and stretch to your 2d animations.
More info relating to the new Grease Pencil additions here:
Secondly, aside from these new additions, a guy called "Antonoiya" is busy preparing the release of GP Tools, which will extend the Grease Pencil functionality of Blender with a library function and other useful scripts.
And, of course, these 2.5d animation tools can be freely combined with Blender's existing 3d (character) animation and visual effects tools such as particles. For example:
Another nice example, showcasing a 3d environment, with a 2d animated character.