A very useful and well-designed tool: IRC chat archive and search. From Techcrunch: "IRSeek is indexing public Internet Relay Chat (IRC) channels at the rate of 6 million conversations a day. 300 million conversations have now been indexed by the company. The most popular networks, including EFnet, DALnet, Freenode and QuakeNetUndernet, are all being monitored - IRSeeK is now “listening” to 2000+ channels across 10 networks."
Apart from being an obvious look-up tool for tech questions, it can also be used by aspiring playwrights. The way it probably works is by having a chatbot joining every open channel on a network and recording conversations.
IRC brings up so many decade-old memories, too.