Yahoo! has closed the gap on Google’s 2006 revenue from online advertising because it keeps a greater proportion of advertising spend, according to soon-to-be-published data.

Revealing contents of an imminent report into portal site economics, Jupiter Research analyst David Card said market share at the big four broke down as follows in 2006:-

  • Google – 17%
  • Yahoo! – 16%
  • AOL – 8%
  • MSN – 7%
  • All others – 52%

Jupiter’s figures are based on ad revenue after payments issued to advertising partners, suggesting Yahoo! holds on to a greater proportion of search marketing spend.

Earlier eMarketer figures that did not account for these so-called “traffic acquisition costs” had placed Google’s revenue share way ahead of Yahoo!’s at 25.3% against 18%.

And latest figures published by eMarketer yesterday using the same calculations project that lead will extend still further by year’s end…

  • Google – 32.1%
  • Yahoo! – 18.7%
  • AOL – 9.1%
  • MSN – 6.8%

… meaning the big four portals make up 66.6% of the total online advertising sector revenue, while the leader gobbles up a third.