The dark web is the darkest place of the internet where most of the sites involved in illegal activities like here the user can buy database, virus, organs, weapons, drugs, counterfeit, funds transfer, hosting, gadgets and much more without any tax fee. and all things users can buy with the help of cryptocurrencies like Bitcoins, Monero, Bitcoin Cash and etc.
In United States jurisprudence, there is a distinction between the mere act of linking to someone else's website, and linking to content that is illegal (e.g., gambling illegal in the US) or infringing (e.g., illegal MP3 copies). Several courts have found that merely linking to someone else's website, even if by bypassing commercial advertising, is not copyright or trademark infringement, regardless of how much someone else might object. Linking to illegal or infringing content can be sufficiently problematic to give rise to legal liability.Compare  For a summary of the current status of US copyright law as to hyperlinking, see the discussion regarding the Arriba Soft and Perfect 10 cases.
Another example when the “nofollow" attribute can come handy are widget links. If you are using a third party's widget to enrich the experience of your site and engage users, check if it contains any links that you did not intend to place on your site along with the widget. Some widgets may add links to your site which are not your editorial choice and contain anchor text that you as a webmaster may not control. If removing such unwanted links from the widget is not possible, you can always disable them with “nofollow" attribute. If you create a widget for functionality or content that you provide, make sure to include the nofollow on links in the default code snippet.
Paid search results are those in the top and bottom of the results page, indicated by the small “ad” icon. These are placements that businesses pay for to show up when users search specific keywords. Google Ads can be a very effective way of utilizing ad spend for those who are new or struggling to compete against businesses that rank higher in organic search results. It’s also great for businesses targeting keywords with high revenue potential.