The concept of online search engine should cover only those services whose primary function is to index, crawl and retrieve information on the internet in response to a user query, regardless of the technical infrastructure used, the language of the indexed information, the date when the information was published, the geographical area of targeted recipients, the revenue model or the means of storage used. The concept should not cover services which merely list or display pre-indexed information, such as online marketplaces, app stores or social networks, even if they have search functionality as a secondary or ancillary feature. Nonetheless, the concept should cover services that index and retrieve information across the world wide web and services that provide search functionality across multiple online platforms or across a significant part of the web. Hybrid services, such as services that combine indexing of information across the world wide web and other information sources, are covered by this Regulation to the extent that they provide search functionality across the web. If the provider of such a hybrid service already qualifies as an online platform because of other features of its service, those obligations and features should apply to the entire service provided by that provider. An online search engine should be presumed to be offered by the provider to recipients in the Union if its website or application is accessible from the Union, unless the provider demonstrates that it does not intend to make its service available to users in the Union.