Few .onion sites now exist as alternatives to the Hidden Wiki as there was originally only one Hidden Wiki. Many alternatives are due to the frequent interruptions and instability of the original Hidden Wiki, while others are used to filter child pornography.
The Dark Web is the part of the internet where all illegal business is done. You can access the dark web through TOR (The Onion Router). Private Wiki is the name used by censorship-proof wikis that run as Tor private services that anyone can edit anonymously after registering on the site. The homepage here serves as a directory of links to other .onion sites. Thus, the hidden wiki is also accessed from the TOR browser.