Tensions between the two rivals increased in 2011 after Benioff posted some disparaging comments on Twitter during Larry Ellison's keynote at Oracle Open World.

Speaking today at Dreamforce, Benioff said: "We are not invited back to Oracle Open World this year for some reason, I don't know why?"

, Oracle offered Benioff another time slot on Thursday morning - when he was on his way to speak at another event in Ohio.

Using Twitter, he drummed up enough interest to hold a rogue keynote address to an overflowing room at a local San Francisco restaurant at the time he had been originally scheduled to speak.

"Larry just cancelled my keynote tomorrow!" Benioff Tweeted, inviting people to join him at the local restaurant instead. "Beware of the false cloud," he added. In another message on Twitter, Benioff said "The show must go on! Sorry Larry!"