The bonding of the rebar (also known as a Ufer ground) has become required in my area as an additional bond for a service. Ground bars, cold water, building steel (if present), rebar (if present), etc.
"http://www.psihq.com/iread/ufergrnd.htm" for more info on Ufer grounds. This was the first site I hit following a quick search. I think it's interesting.
