I've never felt there was an inherent conflict between using an agile approach to development and having a high-level roadmap. The latter sets out your destination, where the former is about figuring out the details of your path to that destination as you go.
I'll be leading a workshop on roadmapping with an agile bent at the MVP Conference in Arlington, VA May 18-19. I had a great conversation with Elliot Volkman about agile approaches to roadmapping, as a warm up to the conference.
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