Both Federal and Pennsylvania state law authorize the signing of contracts by email or other electronic means. In both cases, the parties must agree to conduct the transaction by electronic means, a determination that is made by the context of the transaction and the surrounding facts and circumstances (such as the conduct of the parties). Under both statutes, certain contracts, such as wills, testamentary trusts, family law contracts, and certain commercial contracts are not covered and those agreements must be signed by pen and ink. More stringent rules apply to consumer contracts.
These cases and statutes are a wake-up call to anyone who relies on email exchanges to move transactions along (basically, everyone in the business world). To avoid having an email be treated as an unintentional contact, be careful what you say in the email (good advice under any circumstances) and consider including language that indicates that there is no binding agreement until both parties sign a formal written document.