A Statistical Justification For IE Ads

We’ve all seen the ads. They seem to have found a spot on almost every television channel and Hulu sponsor block. A few months ago, Microsoft released the commercial for Internet Explorer 9, titled “Welcome to a more beautiful web” and it is surprisingly very cool. If I didn’t know any better, this ad might make me want to go give IE a spin right now; but let’s not get carried away here.

Despite what you might think about the historically plagued browser, it is useful to analyze Microsoft’s tactics here. The most common question I’ve heard in response to this ad is “why would Microsoft bother with an ad for their free web browser?” Notwithstanding the fact that Google has been running Chrome commercials for years, this is a valid question. Fortunately, the answer is simple: it all comes back to Bing.

In order to take a closer look at this, let’s examine some of the statistics. The ever-useful Wikipedia claims that Internet Explorer has a 23.7% footing in the browser market. In parallel, it has been observed that Bing has a 15.9% market share for search engines. And a report from Chitika tells us that 72% of Bing search queries come from IE users. So, let’s break that down in more readable terms:

Probability of a user searching with Bing, P(B): 15.9%

Probability of a user browsing with Internet Explorer, P(I): 23.7%

Probability that a Bing user is browsing with Internet Explorer, P(I|B): 72%

Probability that an Internet Explorer user is searching with Bing, P(B|I): ???

That last statistic is the important one for Microsoft. When users search with Bing, Microsoft makes ad revenue. So what are the odds that an Internet Explorer user will search with Bing? Fortunately, Bayes’ Theorem makes this easy to figure out.

P(B|I) = [P(I|B) * P(B)]/P(I)

= (0.72*0.159)/0.237

= 0.48

This implies that 48%, or roughly half of all Internet Explorer users are searching with Bing. This is a clear area for potential growth for Microsoft and the commercials make perfect sense. Get more people to use IE and more will use Bing. When more people use Bing, more money will be made from ads. And if they keep up with these well-made TV placements, they might just convince a few people.