7. Searching
One way to dynamically add new links is in response to a search query. Obviously, this only works if search engines are built into the hypermedia environment. Most hypermedia authoring environments such as HyperCard, ToolBook, etc. have their own search mechanisms of vastly different capabilities built in. Open hypermedia systems such as the world wide web, on the other hand, offer information providers and authors great flexibility in implementing their own search subsystems.
This chapter introduces tools for searching in large information spaces. While those tools can be used for searching in any large information collection, they have now all been either adapted to or even specifically developed for the largest information space of all, the web. Contrary to the simple browsing mechanisms discussed in section 3.2, the tools described here allow to do Boolean, vector space, or probabilistic searches as discussed in chapter 1 "Short Introduction to Information Retrieval".