I applied ED2 to BU, but I already submitted my application a week and a half ago, along with all of my other schools, and i have gotten confirmation of receipt of my apps from all of them. Does anybody know if they will start reviewing my application immediately or if I am going to have to wait until the actual deadlines? thanks
You are asking two different questions. They begin reviewing apps as they come in. This explains why some people get likely letters. It would be a huge amount of work to try and review all apps a soon as the clock strikes midnight on deadline day.
Sometimes Colleges will release decisions a few days early. That isn’t going to happen for any Ivy schools, as i assume you have applied to some, going by your username.
As an aside, I have to wonder what happened to Ivy hopefuls 1-412? 
Good luck to you!
@Lindagaf thanks for the reply. 413 is my area code haha. Also what is a ‘likely letter?’
A likely letter gets sent to students that a college definitely wants. Hardly anyone gets them (at least at tippy top schools), and they are usually associated with Ivy Leagues. They send it because it’s too early to actually say that you are in, but they want you to want them too, and not deposit at another school when the time comes. They basically say “we are almost certainly going to accept you, barring some disaster on your part. Please emotionally attach yourself to us.” My D got a likely letter, but it was from a state school. She didn’t go there, but it was nice to know they wanted her well before decisions were released.