Sounds like we may have talked to the same guy. I agree that breadth of data is a challenge, and I didn't have the chance to push its limits. Though I was surprised that it knew about acids but not about the pH levels. That might be ok--and certainly fixable if it matters to enough people--but it's a reminder that there will always be holes.

It is interesting to imagine an approach like this raising the bar for information quality / provenance on the web. That would be a delightful outcome wrt information accountability.