I would expect that at least a few HN readers are like me: past developers, who now spend the bulk (if not all)of their time managing projects. In response to q

I would expect that at least a few HN readers are like me: past developers, who now spend the bulk (if not all)of their time managing projects. In response to questions about the vertical axis, my answer is that from a PM perspective, it's the measure of how much the developers want to play with the latest technology. From a developer perspective it's the measure of "perceived benefit" from applying a specific technology. Having seen a lot of sexy technologies fall by the wayside over the years (often because they turned out to cause more problems than they solved - yes I'm talking about you, CORBA), my sympathies are with the PM view. When I was a young programmer, we had similar "discussions" with the old guys about the merits of C versus COBOL/VSAM versus RDBMS/client-server versus dumb terminals. As far as I'm concerned, if you can show me (the PM) a quantifiable benefit of using a new technology, I'll consider it. But in a lot of cases, the benefit seems to be "it's cool, and I want to try it." I sympathize with you, but that's not enough to justify the risks I'm taking on by using a new technology.