It can be tempting to use emails alone to form contracts, but you’re walking into a minefield of many hazards. This was highlighted recently by a case in California where a contract over email alone was not upheld. One of the parties did not agree that they were signing a contract when they wrote their name on the email, and the judge agreed.
The difficulty with proving eSignature over email that this case demonstrates is that, in the wider context, most people write their name on their emails as a matter of course, perhaps due to politeness or formality. When you’re seeking to create a contract over email alone, you need to be sure that you can demonstrate the other party wasn't just doing what they usually do with an email 99% of the time.
Legalesign eliminates this risk, the signing procedure has multiple steps and clear written information to signal to all signers that the formation of a contract is underway.
Read more about the court case here: http://www.jdsupra.com/legalnews/electronic-signature-esignature-court-23096/.