Pennsylvania business lawyer Anthony Cerminaro has a post on Legal Issues in Internet Contracting.  The post references a comprehensive article from attorney Karl Belum of the Thelen Law Firm’s San Francisco office. 

The article provides an excellent overview of the issues involved in Internet contracting.  Belum advises:

"Entities engaging in repeat transactions can contractually adopt agreed upon digital signature/electronic commerce ground rules which will be enforced. Entities engaging in single, high value transactions with parties with whom they have no ongoing relationship may still wish to utilize conservative methods such as confirming faces or paper documents."

My experience is that many business people are still confused by what constitutes an enforceable contract over the Internet.  If you are engaging in a single transaction with whom you have no ongoing relationship it is probably excellent advice to utilize paper documents.  But if you are running an eCommerce Web site that may not be feasible or fit into your business plan.  In those instances you will want to set up Web site policies which eliminate any ambiguity as to when or how a contract is entered into.

If you run an eCommerce Web site or regularly conduct business on the Web you may want to check out Internet Laws Affecting Your Company written by Brett Trout.  The book is a great resource.  I highly recommend it.