"CPM (cost per thousand) will probably stay flat and might come down -- in Asia and worldwide," Ryan told reporters in Hong Kong at a news briefing on Thursday.
CPM indicates the price advertisers pay for promoting themselves on the web. Lower CPMs would mean better and more efficient results for advertisers, according to Ryan.
However, Ryan said advertising expenditure should increase over the next five years.
"The real driver of health in Internet overall ad spending is the amount of money that goes in there," Ryan said.
Stephen Moss, the chief executive officer of DoubleClick Asia, said CPM has been coming down because dotcoms have slashed prices in order to bring in revenue, and advertisers have not increased their spending quickly enough in the meantime.
DoubleClick Asia was set up in October 1999 as a joint venture 80% owned by Asiacontent.com Ltd (IASIA) and 20% owned by DoubleClick Inc. The latter is scheduled to take over DoubleClick Asia in 2002.