Brian Smith has the scoop: Shopzilla now displays filtering options above the search results, when most of the CSEs still display them on a left column. However, Shopzilla is not the only CSE to display filters on the top. In Europe, Kelkoo and Twenga have implemented such display.
When we launch the new Kelkoo redesign last year, I remember we came with the question: should we change and display the filters on the left? Everybody in the company had its own opinion on the subject, but there was not a strong majority for filters at the top vs filters on the left. We did some user testing to compare the two options, and didn’t show one option was better than the other. So based on this user testing and other design factors (ability to display LRECs, get a right-hand side column for contextual modules…), we kept the filters at the top :)
In the end, I think the main question to choose one or the other option is the following: do we want users to easily scan and understand all the filtering options that are available, without having to scroll down? Or do we prefer getting the maximum numbers of search results above the fold?
The Shopzilla approach (that is very close to the Twenga implementation) tries to solve this problem with a very compact implementation of filters: by default, when no filters are selected, only filter names are displayed; by clicking on one of them, a list of available values is displayed in a drop-down; when selecting a value, the filter name is replaced by the selected value. This is really a clever implementation, even if I find some details confusing or misleading:
And you, do you have an opinion where the filters should be displayed? :)