On Tuesday, Dave Winer teased us with “My own teaser. First there was RSS 2.0. Then Web 2.0. Tomorrow, the next 2.0. “;->” On Wednesday, Dave pointed to the public review of OPML 2.0 specification. Outline Processor Markup Languages lets you create, validate, communicate, exchange, link outlines with others. There’s a lot of power in that simple concept, and a well-thought out specification by a man who’s been thinking outlines for a long time. Check it out and think about how you could use it in your systems.