Search engines such as Google, Yahoo etc sell keywords or phrases to the highest bidder. When a user enters the keyword or phrase into the search engine there will be a list of 'sponsored results' at the top of the page (and with Google on the right hand side) and below that will be 'natural' results. If an advertiser has purchased a particular keyword and this keyword is entered then their site will be listed in the sponsored results.

The ECJ ruled in a combined case that the use by an advertiser of a keyword that is identical to a registered trade mark constitutes use of that particular trade mark in relation to goods and services. This question of 'use' is one of the essential elements in order to show trade mark infringement in the EU. In basis therefore the ECJ determined that prima facie the use of a keyword that is idential to a registered trade mark for goods and services that are identical to that of the registered trade mark constitutes trade mark infringement. Interestingly the ECJ also held that Google itself did not infringe EU trade mark law as they did not 'use' the marks.