at this moment = NOW (literally and immediately) See more phrases using MOMENT here (You will have a lot of frequently used expressions to use in future ) : http://idioms.thefreedictionary.com/moment

This is a structure with a specific usage. It replaces the word "now" to emphasize strongly that the speaker is talking about the present time in a very literal, immediate sense. So, "At this very moment" are you waiting for this answer? If you have wandered away and plan to check back soon, you might say you are now waiting for an answer. But if you are sitting there as i am typing this, staring at computer, you are waiting for an answer "at this very moment"!