Even as the internet increasingly offers TV-like ad opportunities, 70 percent of buyers - gathered from a MediaPost readers list - say they make buy commitments only three months in advance or less, according to the site. A full half of those surveyed say they buy media less than two months in advance, with 20 percent indicating they tend to buy in the two-to-three month period prior to media runs.

A slight increase in campaign durations was noticed, with 24 percent of respondents saying their client campaigns had grown and 14 percent indicating they had shrunk.

Sixty percent said client campaigns remained at about the same duration as previous campaigns.