A number of us, including this blog, have gotten this story wrong. It's time for a correction.
The USPTO has NOT invalidated the Blackboard patent. Instead the USPTO is proposing to invalidate the patent and has issued some preliminary documents for review and comment. At the end of the day the USPTO still might uphold the patent as valid.
Nuances matter. The East Texas Court is under no obligation whatsoever to recognize the current state of play within the USPTO. The jury in Texas has ruled that Desire2Learn's product infringes Blackboard's patent. The judge in Texas has issued an injunction against D2L for use of its product and future sales. The injunction kicks in on or about May 11th. Given Blackboard's public statements there is no indication they are throwing in the towel and are ready to back off anytime soon.