[nolok]

A bit of a misleading title. Ebay is questioning whether an big established, household brand like them still need to pay ads in Google search, because those users would come to them anyway.

In the same vein, google search ads probably have low value for facebook too.

[netrus]

I could imagine a user using Google just to circumvent the category hierarchy of a site like Ebay, e.g. searching for "Ebay washing machines". If this user clicks an ad on the result page, it is super painful for Ebay.

[OGinparadise]

It may have to do with search boxes being built in browsers already. Type and search, instead of going to ebay and then type-search. eBay may be bookmarked but it's still not as easy to pull up as searching from a browser's window.

[makomk]

Ebay's taken a bit of a scattershot approach to advertising on Google from what I can tell - they seem to have bought ads for a huge number of almost random keywords.