Hi.
Dumb question probably, but are banner impressions

a. views of your banner
b. actual clickthrus on your banner

i.e. if I pay for 50,000 banner impressions will my banner be SEEN 50,000 times or will it be seen for any amount of times until it has had 50,000 clickthrus?

Please explain

Impressions means your banners get SEEN, as opposed to "visits", or "click=thrus".
So, if you pay for 50,000 impressions, your banner will be seen 50,000 times, but it may or may not get any click-thrus. Make sure you have a GOOD banner that people will want to click on.

Thank you - exactly what I wanted to know!

Now I just need to make a good banner...