The Unofficial Guide to StumbleUpon | Stumblers.net. Invisible Web Tutorial. What is the "Invisible Web", a.k.a. the "Deep Web"? The "visible web" is what you can find using general web search engines. It's also what you see in almost all subject directories. The "invisible web" is what you cannot find using these types of tools. The first version of this web page was written in 2000, when this topic was new and baffling to many web searchers. Since then, search engines' crawlers and indexing programs have overcome many of the technical barriers that made it impossible for them to find "invisible" web pages. These types of pages used to be invisible but can now be found in most search engine results: Pages in non-HTML formats (pdf, Word, Excel, PowerPoint), now converted into HTML.
Why isn't everything visible? There are still some hurdles search engine crawlers cannot leap. The Contents of Searchable Databases. How to Find the Invisible Web Simply think "databases" and keep your eyes open. Examples: plane crash database languages database toxic chemicals database. Tutorials on Everything. How to Use Windows XP. Essential Office XP Tutorial.