Abstract
The internet encompasses a large number of documents to which search engines try to provide access. Even for many narrow topics and potential information needs there are often many web pages online. The user of a web search engine would prefer the best pages to be returned. Web search engines and information retrieval research have responded to this need and developed systems for quality assessment. This paper gives an overview on common algorithms used for this task and discusses new research directions which try to improve the results of quality assessment.