So basically I want to be write a P2P-software that is able to send text messages to all nodes, kind of like IRC. What kind of network am I adviced to use? I've looked some into DHT Kademlia, and it seems easy enough to implement, but it doesn't appear to be useful for what I want to do? What kind of protocol does Skype, for example, use?
edit: and I forgot to mention, it doesn't have to be instant messaging, a latency of several minutes is more than acceptable. I don't suppose I could continously try getting the data corresponding to the to the current time every five minutes or something on all nodes?