Whitney and I both worked in the 1970s for I.P. Sharp Associates, which used an email system written beautifully in APL by Leslie Goldsmith. Most user names were simply our initials. Ian Sharp was IPS, Leslie LHG, and Arthur ATW. (Middle name Taylor.) I’ve been SJT ever since (including to two wives) but was not smart enough to grab the domain: see 5jt.com.