REDMOND, Washington: Microsoft is to begin testing a new way to measure the effectiveness of online advertising.

Engagement Mapping is a departure from traditional 'last ad clicked' metrics. Instead, it takes into account all web interactions which lead a consumer to making a purchase, thereby offering marketers a more accurate assessment of how to plan an ad campaign.

The trial follows the software titan's $6 billion (€3.97bn; £3.03bn) acquisition of web marketing agency aQuantive to capitalize on the booming online ad market and better compete against arch-rival Google.

Declares Brian McAndrews, svp of Microsoft's advertiser and publisher solutions unit: "The 'last ad clicked' is an outdated and flawed approach because it essentially ignores all prior interactions the consumer has with a marketer's message."

He adds: "Our Engagement Mapping approach conveys how each ad exposure - whether display, rich media or search, seen multiple times on multiple sites and across many channels - influenced an eventual purchase."

Microsoft's ad clients and partner agencies, such as Initiative Media, have signed up for the program, which begins beta testing on March 1. Initial results are expected to be available before the end of the second quarter.

Global online advertising will grow from $45bn in 2007 to $147bn in 2012, and account for 21% of all ad budgets by the end of that period, according to a Kelsey Group forecast earlier this week.

Data sourced from (UK); additional content by WARC staff