XMPP is an open, real-time instant messaging platform that is useful for sending and receiving notifications between servers and humans. You can use it to receive administrative notifications from your website or to push notifications to subscribers much more efficiently than current poll-based solutions such as RSS. This course will teach you to work with XMPP from Ruby.
Casimir Saternos has been developing software for the past decade. He has written a number of articles that have appeared on the Oracle Technology Network and collaborated on several projects for PeepCode screencasts (now Pluralsight).