Wikipedia says Nginx started in 2004. If you look at the state of things for threads and other "lots of sockets to deal with" things in that timeframe, you can

Wikipedia says Nginx started in 2004. If you look at the state of things for threads and other "lots of sockets to deal with" things in that timeframe, you can see multiprocess was probably a safer choice, especially if you intended on running well on a variety of Unix or Unix like OSes. This page has some of that state captured pretty well: http://www.kegel.com/c10k.html http://www.kegel.com/c10k.html