I just read an interesting article on the PC PRO website which reports the findings of a study on online marketing that shows that having targeted banner campaigns leads to a lower conversion rate than non targeted banners. The explanation providied is that the targeted banners are viewed as a privacy violation.

However, targeted text adverts do well (just look at google adwords) and non targeted banners seem to stick in people's minds more when making purchasing decisions.

The research by Toronto University used data from almost 3,000 online marketing campaigns and suggests that having either targeted ads or banners ads in their own right would yield higher ROI. It is debatable whether having two ad areas on the page, one targeted and one banner would improve results. A study by the UIniversity of Michegan on advertising placement looked at banner placement to assess relative effectiveness. This study found inconclusive evidence to support the theory that having two advertising campaigns on the same page improves clickthrough rates.