rango - 1:05 am on Jul 15, 2012 (gmt 0)
What Matt said also ignores other factors on the page. Let's say that a page with 2 sentences also has 2 ads on it. In fact, the 2 sentences could drop below the fold. In that case, I don't think it's unreasonable to expect it to be considered thin again. And I don't think his statement rules that out. If however it's an ad-free page with 3 unique sentences, then it does make sense for that to considered enough.
I think the fat/thin ratio is a good theory and much in line with my own thinking. I'd imagine it's not the *only* factor though - I believe there's also a duplicate/non-duplicate ratio at play, though I think that existed prior to Panda.