there is actually no precedent for emails, as yet/to my recently researched knowledge. The only thing that is off help to students at the moment is the EU E-Commerce Regulations.
Otherwise you are going to have to look at other nstanteous communications. Also, back to the acceptence, it must be "communicated" unless conduct substitutes. Consider the policy rules behind the postal rule. Also, there are cases out there that deal with incorrect postal addresses that were held not to be valid...