I've played around with it, but I actually wasn't too impressed. The problem is with synonym databases. While words can mean the same time, depending on the context, they often don't. I have a few ideas on how to do this, though.
With how much money stands to be made in auto-spun, I imagine others are already rushing to get this done, but I have a feeling they're looking in the wrong place.
I'll also be releasing some project management software (SaaS too) next month. So be on the lookout for that!