You are, of course, right — I played a bit loose and fast in assuming that the different keywords that have similar amounts of searches on Google would convert into clicks for the link in the top of the SERPs. You’re right that it depends upon the relevancy and position and link text + description.

It’s also hard to compare between the search engines, since they have very different page layouts for their SERPs — some of them are using custom templates for particular types of keyword searches.

While admittedly I ignored all these other factors that could affect click-throughs for the top position, I’ve hopefully helped folx out a bit by providing a loose estimation method for how valuable top position can be vs. second position, and also maybe helped in showing a loose estimation method for relating terms of similar volumes of searches to one another on Google.

You’ve inspired me to consider doing some similar studies with the other major search engines, too!

Thanx for mentioning my post.