I'm a little skeptical- why can't core developers build contracting into the blockchain so that it is totally decentralized? I suppose my question is, why do we need a company, BlockSign in this case, to perform this function?
This IS totally decentralized contracting built into the blockchain :). The link above is to a specification that allows everyone can create contracts in a consistent manner. It's independent of the company, Blocksign, who offers packaged a way for consumers to do it, but any developer (or determined consumer) can use the specification to create contracts themselves that will be compatible with any other system created with the same specification.
Worked great!
I'm glad to hear that. (one of the developers here) But what do you mean exactly by "worked"? You mean you have tried the implementation on blocksignit.com ?