The deep web is host to primarily legal, even mundane content. The sections that aren't legal are dominated by drugs, fraud, and combinations of illegal activity - primarily the major deep web markets. Just because the majority of the content is legal, though, doesn't mean it's safe. Legal content has the potential to be damaging, even dangerous. Most of the deep content is categorized by: Legal; Explicit; Drugs; Pharmaceuticals; Fraud; Multiple Categories (Illicit); Falsified Documents & Counterfeits; Exploitation; Hacking & Exploits; Weapons; Extremism; Other Illicit Activity; Downloadable content (movies, music, books, etc); Unknown/Web sites that are down. A research made by Terbium Labs (which is a dark web data intelligence company) has proven by many tests to various URLs that when it comes to deep web content, more than half of it is legal. Here's what they say in their book: Legal Content On The Dark Web The dark web has a bad reputation because of its structural anonymity and emphasis on privacy. We hate to break it to you: the dark web is mostly legal. Legal content comprises 53.4% of all domains and 54.5% of all URLs in our sample. Here's a graphic with an estimate of the values in percentage that make up the content of the deep web: TL;DR: The deep web is not worth your time and my opinion is that you shouldn't visit it.
Who decides what the hell is legal on the Internet? The UN? Half their funding comes from the US and we like to say we have the best justice money can buy.