My employer often contacts me on chat and explains me what the next project is about. He does most of the talking, I just sometimes ask questions and throw in the occasional "okay" and "sure". These words get awkwardly repetitive in longer conversations and I'm looking for some other terms of acknowledgement.
Yes, right, I see, understood, yep, certainly, of course, definitely, ok, OK, indeed, quite, go on... or just nothing.
If this is all typed in IM and not spoken out loud, you might not need to acknowledge as much for longer chunks unless there's something you don't understand.