Definitely a great read, one I recommend frequently. Nowadays, I reach for ASIO. I think I read yesterday it's going to be included in C++17? Much more portable than POSIX sockets. After reading this I implemented a multithreaded version [0], then started contributing to h2o [1].

[0] https://github.com/nickdesaulniers/c-http-server/blob/master...

[1] https://github.com/h2o/h2o