Dark web monitoring is these days considered a required part of threat intelligence gathering. Deep web monitoring is increasing the amount of valuable threat intelligence but usually hits on financial or other limits. The majority of hidden sites require paid or invitation-only membership, the sites are usually in other than English languages, the sites use various robot/spider blocking techniques such as captcha, puzzles, interactive problem solving, or even require proof of an attack to discourage security researchers and threat intelligence analysts gathering new threat intelligence.
We decided to be unique, and gather as much as possible threat intelligence by indexing not only the dark web but as well the deep web. We will not disclose the used techniques, tools, and processes used to gather the threat intelligence, but on a daily basis, we index MILLIONS of dark web and deep web pages. According to our research, our engines can be compared with one of the largest dark web search engines which provides search capability on 1.5 billion dark web pages (and no visibility on the deep web).
We do not provide access to our search engines, we actively cooperate with our clients defining the keywords, understanding the context, and providing customized threat intelligence back to the clients. You pay per keyword/context and on a daily basis, you get back threat intelligence. Specialized topics requiring additional efforts are more expensive.