The Ultimate Chart - For those who like to keep up on the latest trends in pop (read sales)
"By standing on the shoulders of giants. The Ultimate Chart is an unprecedented aggregation of timely, relevant metrics and a product of our friends' and partners' hard work and well-deserved success. We analyze and integrate information about music everywhere -- from Amazon and iTunes and YouTube and VEVO and Pandora and Clear Channel and Myspace and Facebook and Yahoo and AOL and many, many others."
Probably more accurate than Billboard.