This morning, Roger pointed me to this blog posting about the top search results for 2006 for three of the major search engines. While the posting is pretty humorous, it may explain SharedPlan's pay-per-click (PPC) results with Google and Yahoo.
Because SharedPlan transacts all sales through the website, PPC advertising is the largest component of the company's marketing spend, and the company advertises on Google, Yahoo, and MSN. Even though the search terms SharedPlan purchases are about the same on all of them, the productivity of each engine is dramatically different.
For search-only results (ignoring content results so that I can compare apples to apples), Yahoo provides about half the number of clicks that Google does. (MSN numbers are so small that I'm not even going to describe them.) Given their relative share of total search volume, that may not be that surprising. However, they differ dramatically in their clickthrough rates, with Google providing six to seven times greater clickthrough rates. The difference becomes more magnified when you consider the rate a which these clicks become conversions, which in the case of SharedPlan means when the prospect downloads trial software. The conversion rate for Google is 2.5 times that of Yahoo.
There are a lot of factors that may lead to these differences, like the ads for Google are structured and displayed differently than for Yahoo, even though we use the same messages in each. Alternatively, the explanation could just be their different users, as illustrated by Nicholas Carr's list.
Or it could just be black magic ...