It's a company that pretty much owns the education market, despite their products being nearly universally considered to be harmful^H^H^H^H^H^H^Hhorrible.

For more information, see wikipedia: http://en.wikipedia.org/wiki/Blackboard_Inc

Edit: I should point out that my knowledge of blackboard is near non-existant, I haven't had to use it in any of my schooling (university in central florida, public education in silicon valley), so I don't have a useful opinion of it.