It is impossible to measure or put estimates onto the size of the deep web because the majority of the information is hidden or locked inside databases.
However, since more information and sites are always being added, it can be assumed that the deep web is growing exponentially at a rate that can not be quantified.
Goby, a free service, is a deep web search engine that searches selected databases on the web focused on 400 categories of things to do while traveling.
However, many of these resources run the risk of turning into deep web or invisible web resources, since they frequently can not be located by search engine crawlers.
The eight arms are joined by a deep web, with about 35 small suckers on each arm.
Deep web content is not indexed by standard search engines and so does not appear in standard search engine results.
Deep web crawling also multiplies the number of web links to be crawled.
It provides simultaneous access to deep web scientific databases, which are typically not searchable by commercial search engines.
