I'd like to see explanations like this on the basics of p2p networking, like we already take for granted for decentralized systems.  Same principles should apply to cryptocurrencies, right?  I've used bittorrent for like 15 years and I'm not sure how discovery works on those networks, same with Tor. 

Wikipedia says that in the early days, many systems used IRC channels for announcements, but that can't be current anymore?