The reason for the growth is a combination of more searchers and the fact that the Google brand draws more searches, said David Hallerman, senior analyst and the report's author. Indeed, there are expected to be 144 million U.S. search-engine users this year, rising to 166.2 million by 2010. And, in terms of total paid-search ad spending, Google's share is expected to reach 57.2% in 2006, up from 32.9% in 2004.
"The largest reason for Google's growth is because of the Google brand," Mr. Hallerman said. "For the average user, Google is the equivalent of search."
Google has been wise in diversifying its business into content offerings, like Google Finance, which it introduced last week, the analyst said. "If Google can figure out how to do that in TV, with either video on demand or digital video recorders, and they can extend the technology of delivering relevant results, there would be even more of a gold mine," Mr. Hallerman added.
Beyond 2007, Google will contend with pressures -- like click fraud and privacy -- that "will potentially chip away at, if not halt, the growth of search engine marketing," the report said.