If you're an expert, please bear with me, as some of what follows will seem elementary to those already familiar with the online advertising world. If you're not, I hope this gives you a better understanding of how advertisers, publishers, ad serving companies, agencies and other companies such as Google all fit into this exciting new mix.
That's why when we have FastCGILighttpd is good, but is best used in specialised instances, for specific (mainly static content) tasks. Its pointless using it for PHP as the cost of forking out a process to run the script will outweigh any saving from running a lighter-weight http server.
We warn the reader in advance that the proof presented here depends on a clever but highly unmotivated trick. -- Howard Anton, "Elementary Linear Algebra"