Agreed...someone on BP wanted to know why Posey wasn't on the list...and my answer was that I highly doubted anyone from ESPN had seen one of Posey's workouts this Summer, which is where both Rivals and Scout said he blew up.
For further discussion here are some of the links (all free, I believe):
ESPN.com - NCF - RecruitTracker 2008
ESPN - WR Julio Jones tops 2008 ESPN 150 - Insider
ESPN - Eight ESPN 150 players under the radar - Insider
ESPN - Luginbill: Breaking down the 2008 ESPN 150 - Insider
ESPN - Get to know: ESPN 150 WR Julio Jones - Insider
ESPN - Hill has plenty of options - Insider