Collegeboard.com actually redirects to Collegeboard.org, the website of the largest and most widely used college entrance examination board.
College board is a private company responsible for exams such as the SATs, and the organisation has actually been running since 1900.
Colleges in the United States and abroad largely base who they accept into their courses based on achievement in the SAT exams, so they are pretty important!
My memories of Collegeboard are all about preparing for SAT exams at school. There are two parts to the SAT test: Verbal and logical (math).
Although schools do their best to prepare you for the college entrance exam, I found a cool video that gives you some additional information.
It's called Three things the college board won't reveal about the SAT:
Also, to learn more about registering for or taking Collegeboad's SAT exam, then I found this other Blurtitt answer covers most of it: