Two-way RSS
Microsoft announced yesterday the specification for Simple Sharing Extensions (SSE) that "extends RSS from unidirectional to bidirectional information flows". Ray Ozzie, Microsoft's CTO talks about it in his blog. The spec itself is available on MSDN as is the FAQ.
A VC calls it the second coming of RSS, as does Richard MacManus from Read/WriteWeb. Dave at Scripting News likes it as well. Dick Costolo from Feedburner also has a good post on the subject. Michael Arrington from TechCrunch thinks it's cool and also that new companies will be built with SSE.
I guess this needs to be checked out!