Web indexing means creating indexes for individual Web sites, intranets, collections of HTML documents, or even collections of Web sites.

Indexes are systematically arranged items, such as topics or names, that serve as entry points to go directly to desired information within a larger document or set of documents. Indexes are traditionally alphabetically arranged. But they may also make use of hierarchical arrangements, as provided by thesauri, or they may be entirely hierarchical, as in the case of taxonomies. An index might not even be displayed, if it incorporated into a searchable database.

Indexing is an analytic process of determining which concepts are worth indexing, what entry labels to use, and how to arrange the entries.