There is an interesting article in the Chronicle about the patent. Some of the more noteworthy things it contains are:
"Michael L. Chasen, president and chief executive officer of Blackboard, said the company had no plans at this time to sue colleges that may infringe on Blackboard's patent. "Our focus is on the commercial providers," he said. "We are certainly not interested in going after any of our clients." "
"But Mr. Small [Blackboard counsel] said fears like those expressed by Mr. Schilling were overblown. It would make no sense for Blackboard to go after open-source programs like Moodle and Sakai, he said, because they are not commercial providers. And Blackboard's patent is not at all like Acacia's or Test.com's, he said, because both of those companies have sent letters to colleges demanding royalties. "
"He said many e-learning companies could operate without infringing on the patent, though he declined to provide any examples. However, he also said that had Blackboard not merged with WebCT, then WebCT would have been infringing the patent. "
So they're not going to go after individual schools or after Moodle and Sakai.. But the greater danger is in the chilling effect that that this will have on the marketplace. As campuses go through RFP's the specter of being sued or the company you choose being sued will lurk and will consciously or unconsciously inform every decision.
If however it turns out that they do leave Moodle and Sakai and all the other open source CMSs pretty much along this could really be the one thing that gets that sector going. I see no reason why many schools wouldn't want to go open source after this. If the choice basically is Blackboard or open source many many schools are going to go for the latter. Certainly Wisconsin, Ohio State, Iowa, MnSCU and the other big D2L clients are unlikely to be signing up for Blackboard should D2L land up going out of business.