Off the top of my head, things I never implement or use anymore: * socket listeners * line drawing * explicit memory management * old APIs and libraries *

Off the top of my head, things I never implement or use anymore: * socket listeners * line drawing * explicit memory management * old APIs and libraries * Perl * Assembly And things I rarely use: * Semaphores & other threading primitives * XML * C/C++ Now, knowing these sometimes helps, but the amount of time I spent on them probably doesn't justify the benefit aside from the fact that it was necessary at the time. And somebody is doing these now — I just find I don't need to, as it's always handled somewhere below the abstraction layers where I work. An equally interesting list would be the things I use now that didn't exist when I graduated from college in 1996.