Moments ago, John Cena posted the following on his Twitter account, which was then retweeted by the official WWE Universe feed:

STARTING Monday Night July 23 @USA_NETWORK WILL BE ADDING A 3RD HOUR TO @WWE MONDAY NIGHT RAW - PERMANENTLY. #3hourRaw

UPDATE: WWE.com has posted quotes from Vince McMahon and the co-presidents of USA Network.  It also mentions that starting with the 1,000th episode on July 23, fans will be able to interact even further through social media, deciding match stipulations and more.