They didn't have NLP, but some easy commands and they didn't need to scale much, because I always had below 1000 users at the same time. News bots, filesharing bots, social network/user stat bots, game bots, etc.
Funny that I accomplished to write a news bot that got its data from some news site via sockets by copy-paste and edit some code I found online. I didn't even know what arrays were, let alone half ot the code I copied. But somehow I got the target host changed and the needed data parsed out of the HTML.