Samuel Morse sent America's first telegram in 1838, heralding the occasion with the words, "A patient waiter is no loser." By the late 1860s, a mere 30 years later, the telegraph had replaced the Pony Express, was in established use for commercial transactions, and had been accepted by the courts as a valid means for creating enforceable contracts.
Of course, the telegraph is sort of like an electric pen, and an electric pen is kind of like an ecclesiastical seal, which isn't far from Moses descending Mount Sinai with the decalogue written in stone. At each period in human history, we've deployed the technology available to us to memorialize important covenants in durable media for the purpose of creating reliable records of what occurred.
In those respects, the internet is no different from past media and the courts and legislatures have recognized that. As a curiosity, Silicon Valley's beginnings can be traced back to 1909 and the founding of the Federal Telegraph Company which was funded by Stanford's president at the time and several faculty members as angel investors. More on point, Congress enacted the Electronic Signatures in Global and National Commerce Act (conveniently, ESIGN) in 2000 whose main import was to declare electronic records and signatures equivalent to the pen and paper. Most states have passed the Uniform Electronic Transactions Act, a model state law which also declares the electronic pen and ink pen as equivalents.
Commentators have pointed out, not for the first time, that federal and state legislatures acted too eagerly and wasted their efforts. Lawrence Lessig, in 1995, argued that the law of cyberspace should be developed through the common law, which is the process by which judges make case-by-case decisions drawing from past precedent. As with the telegraph, the courts were already reasoning by analogy that records could be created and signed on the internet. All they had to do was look to the telegraph! In fact, Mr. Jose Arroyo in Florida executed the first paperless home mortgage in 2000, before ESIGN had become law. The loan was closed and recorded in less than five hours down from the average of forty-five days it typically took.
Electronic signatures are now well-established as valid. The rise of electronic signatures mirrors the rise of the internet as B2B and B2C commercial transactions would be impossible without the legal foundation of the validity of electronic transactions. (Although, the, say, online mortgage space wasn't doing that great for awhile.) Nevertheless, the electronic signature is just a chapter in the long history of the writing and the signature.
