Relevant to Blender v2.37
Blender's SoftBody system allows vertices to move based on the laws of physics. This mean that they can be set to react to gravity and wind. Objects in Blender can be set to be a soft body. Only Mesh and Lattice objects are implemented in release 2.37.
The SoftBody system is primarily meant to enhance animation systems, including character animation. Effects like flexible or rippling skin are now very easy to achieve.
In the 2.37 demo files (4 MB) you can find two examples of soft bodies, softbody_basics.blend and wind_soft.blend http://download.blender.org/demo/test/test237a.zip.