IRS e-File
...
program
The first significant large-scale implementation of eSignature was by the U.S. Internal Revenue Service in 2001 (for tax year 2000). Taxpayers meeting certain requirements were able to file paperless tax year 2000 returns complete with an eSignature. Through tax preparation software (such as Intuit's Turbotax) they were guided through selecting a five-digit PIN number and providing two specific items of data from their previous year's tax return. Selecting a PIN number and providing prior-year personal tax information served as an electronic signature for an e-Filed return. According to UncleFed's Tax Board 4,293,085 taxpayers signed their returns with self-select PINs in 2001.
...