well let me see if i can help clear up the mystery.
as Scotter pointed out (great post btw scotter), ESPN, especially, ranks the players based on potential in college. Potential means just that. some highly rated freshmen stumble a bit out the gate only to really come on strong their last 2-3 years. now i have no idea how much Massengale will improve. i'd say she played (performed) better for Team USA last summer than she did for Tennessee this past year. is it coaching? was she struggling with new offense/defense? it's not like she played poorly, but she wasn't anywhere near one of the top 5 freshmen in the country, and everyone had her ranked in the top 5.
so without going into a lengthy diatribe, most of the kids in the top 10 in HS, at some point in college, play like their rankings. some get it early (KML and Williams), and some get it later (Tina Charles became a defensive AND offensive monster midway thru her junior year). still it's no guarantee that a top 10 HS kid will be a top 10 kid in her class when she's a senior in college. but the reason (can't speak for everyone) I bring it up is based on potential and expectations. and after all, ranking the teams 1-25 preseason is all about potential and expectations, right?