Search engine data source

Another characteristic of categorizing is the source which is covered by the search engine data. Most have already described the source. Web search engines collect documents from the World Wide Web. Vertical search engines look at a selected area captured by the World Wide Web, and Web documents only on a specific topic such as football, health, etc.

Usenet search engines take contributions from worldwide distributed for discussion by the medium Usenet. Intranet search engines are limited to the computer of the intranet of a company.

Desktop search programs are referred to the local searchable database of a single computer. If the data collection is performed manually or by means of registration assistants, one speaks of a catalog or directory. In such directories like the Open Directory Project, documents are hierarchically organized in a table of contents by topic.