What is illegal on the dark web? While surfing or accessing any form of internet, you will come across many links that may not be legal. While some are not harmful to your computer, many others can cause a lot of problems. Many times, you will come across sites that offer "free" downloads. While this is true, the user must still put up with all the associated problems. The download links often have spyware or adware on them, which can damage your system and can make it illegal to what is illegal on the dark web