Last week eBay pulled all their campaigns from Google AdWords to protest a party planned by Google to promote Google Checkout that was coincide with the eBay Live event in Boston.

The eBay’s event was overshadowed by Google planned to promote Google Checkout to eBay sellers who used PayPal.

Google said eBay has been refusing to offer Google Checkout as a payment option for sellers and buyers on eBay even after Google had been approached by power sellers to obtain access to Checkout.

When I read the story I wondered how much cash Google lost after eBay pulled their ads.

Greg Sterling of Search Engine Land has written an interesting post of how much traffic eBay received from Google and Google cash lost.

Without citing a source, Did-it’s Mark Simon says in this MediaPost piece that eBay spends — or used to spend — $26 million monthly on Google AdWords in the U.S. market. If true that’s $312 million annually.

I haven’t checked but I am certain that’s quite a large portion of ebay’s annual revenue.

It’s not too surprising to know Google sends the most traffic (organic and paid) to ebay.com (about 45.7% of their total traffic)

I am curious to see the outcome of their action and to what extent Google or eBay will suffer from this debacle.