I was curious if I could find anything out about their stack. Turns out they are using something called Apache Traffic Server[0].
> Formerly a commercial product, Yahoo! donated it to the Apache Foundation
> Formerly a commercial product, Yahoo! donated it to the Apache Foundation
At one point a good majority of the "internet" was served by AOLServer, a multithreaded TCL scriptable server written by NaviSoft and acquired by AOL.