In November of 2005, then Microsoft CTO Ray Ozzie proposed a set of extensions to RSS that would allow the protocol to support replication of structured data between loosely-coupled applications. The concept was simple: just as RSS feeds may be used to publish and subscribe to news articles, contact lists, or calendars. so SSE could allow one or more systems containing stories, vcards, and events to be cross-subscribed with one another. When two or more SSE feeds are cross-subscribed, their contents merge and replicate all changes to each endpoint. SSE is, in effect, bi-directional RSS; it extends RSS by adding semantics to track changes made at each endpoint and an algorithm for resolving conflicts. When multiple SSE endpoints become cross-subscribed, the result is a kind of application mesh, in which data is replicated between any number of systems.