He was a founding board member of the Open Source Initiative and briefly served as its president in 2005.

[10] In 1983, Nelson and Patrick Naughton wrote Painter's Apprentice, a MacPaint clone.

[13] In 1991, Nelson founded Crynwr Software, a company located in Potsdam, New York,[14] supporting deployment of large-scale e-mail systems, development of packet drivers, Linux kernel drivers,[15] and reverse engineering of embedded systems.

[6] On February 7, Nelson published a post to his personal blog titled "Blacks are lazy", which generated controversy.

[25] He transferred the website to Friends Publishing Corporation, a Quaker nonprofit, in March 2018.