Update periods from weekly up to once a year exist. The larger centralised services normally have longer periods between reindexing the same page or server. Some of the services are limiting themselves to the indexing of metainformation or small portions of the documents, others claim to do fulltext indexing. Their interpretation of fulltext varies between extracting significant individual terms, indexing the first 20 lines in combination with other elements, and using the complete document plus certain metainformation. In many cases, not all the indexed information about a document is displayed as part of the search result or is it displayable at all.
Some services show the title of the hits only.
Others prevent the user from inspecting all hits in the result set. Best-match methods are predominant as search software, but the respective ranking algorithms are rarely described in a satisfactory way. In the best of cases, Boolean searching is provided as well. The user is rarely pointed towards the possibility of truncation. Right hand truncation is sometimes used as default.