Are electronic signatures legally binding?

Absolutely. The ESIGN Act is a federal law passed in 2000. It grants legal recognition to electronic signatures and records if all parties to a contract choose to use electronic documents and to sign them electronically. UETA, a precursor to the ESIGN Act, was introduced in 1999 and has been adopted by 47 U.S. states, as well as the District of Columbia and the U.S. Virgin Islands. Among other things, UETA provides that when a law requires either a writing or a signature, an electronic record or an electronic signature can satisfy that requirement when the parties to the transaction have agreed to proceed electronically.