It's also unreliable. If you're looking at a signed piece of paper, how do you really know the signature on it was created by the person whose name is written? There's no metadata behind a written signature that helps you determine it's authenticity.
DocuSign, a company that's been around since 2003, is bringing the legal signature into the modern era. Already the company enables a document to get sent via e-mail to the person who needs to sign it. The e-mail contains a Web link, and on the Web, the signer confirms his or her identity (by answering personal questions provided by Verid, such as "What is your monthly mortgage?") and "signs" the document by clicking a Sign Here flag on screen. The entire transaction is recorded in minute detail--when it was signed, how it was authenticated, and where (which IP address) the signer was located. It provides much more verifiable information than a regular signature. DocuSign stands behind the veracity of the online signature and will back it up in court if need be. It's essentially an online notary.
The latest news is that DocuSign is now offering this capability completely "in session," that is, without requiring an e-mail step in the transaction. Businesses that want to sign (literally) people to a binding deal will no longer require that they wait for e-mail, or worse, physical delivery of a document. It should help companies close contracts faster.