[ineedasername]

I think it had much to do with the fact that it was much more difficult to monetize content delivered through RSS. I recall some sites playing around with delivering ads through it, but it was nowhere near as "robust" a platform for ad delivery as via their own full-fledged sites. And less face it, most content sites really are just operating as ad delivery platforms, so anything that interferes with that will fall by the wayside.