Growth in online search will offset the the downturn in online display and classified advertising in 2009, according to new analysis from Ernst & Young.

Less money will be spent on advertising focused on reach with investment in performance-based advertising, such as search, expected to increase, suggested the ‘media and entertainment by numbers’ report.

Internet advertising is likely to overtake TV advertising this year as the largest ad medium, the report said.

“But to assume that a media accounting for a fifth of all advertising budgets could be totally immune to a downturn would be too optimistic,” the report added.

Publishers will be affected most by the move to more interactive ad models, including cost-per-click (CPC) or cost-per-action (CPA), as this will cause CPM rates for banners and display advertising to fall.

Online classified advertising will be affected more by the general economic climate, for example fewer jobs and properties available, than by changes within the advertising industry itself, the report added.

[Read Journalism.co.uk’s full breakdown of the Ernst & Young report]