This month DoubleClick published a useful benchmark of online advertising performance rates across all activity in 2008.  This is pretty much the most solid data you'll ever see on display advertising performance, based according to DoubleClick on: "hundreds of advertisers, thousands of campaigns, and tens of billions of ad impressions."

It's a useful set of benchmarks showing for instance variations in click rates by size and format of ads.  The data is also split by geography - which shows some fairly disappointing results for the UK.

The table below shows the average click through rate across all formats (static image, flash, video) for the main economies in Europe, plus the United States.  (The DoubleClick report has worldwide performance data for twenty nine countries).

This is really disappointing - and not just for the online advertising industry.  As the Guardian recently pointed out, the British newspaper industry is also desperately hoping for a renaissance from online advertising.

So why the poor performance.  Probably no single reason, but possible reasons would be:

• banner fatigue - advertising creative not being refreshed often enough
• lower percentage of inventory going on larger sizes / more static formats
• larger percentage of media going out across networks which tend to deliver a lower CPC
• more brand advertising versus direct response campaigns

Any more ideas anyone?