Reddit's software is not very impressive. They should really focus on consolidating to a more manageable setup. I'm aware that big sites often have complex environment to facilitate scaling, but frankly, reddit is a big monstrous mess. It'd be a lot simpler to move hosts if they would get some of those extraneous dependencies removed and put some simplicity and sanity into their data storage, instead of the half Cassandra/half PgSQL thing they do now.

I wrote a long post about it here: http://www.deserettechnology.com/journal/reddit-the-open-sou... .