On April 13, 2007, WTI Crude at Cushing lost its status as a gauge of world oil prices[2]. A large stockpile of oil at the facility (mainly due to a Valero refinery shutdown[3]) has caused prices to be artificially depressed at the Cushing pricing point.
This text was added to wikipedia on April 15th
http://en.wikipedia.org/w/index.php?title=Cushing%2C_Oklahoma&diff=122914465&oldid=110207832