A user's view of an online advertisement. Each time a website viewer sees an online ad, this is one impression. The more impressions an ad receives, the more likely it is that a user will click on it. Most online ads are sold by cost per thousand of impressions. See also: CPC.
Abbreviations: CIT = conventional impression technique, CT = computerized tomography, LS = laser scan, MRI = magnetic resonance imaging, poa = post aurale, pra = pre aurale, sa = super aurale, sba = sub aurale, TLIT = triple-layer impression technique.