The Ethereum Name Service (ENS) and Unstoppable Domains are decentralized alternatives to the standard Domain Name Service (DNS).
Essentially, all domain names must be approved by DNS authorities, including domain names which use .com, .co, .org, .biz, .gov, etc. However, in some countries censorship is occurring. For example, in Turkey, there are 150 words that are banned, and domains that use these words cannot be hosted in the country.
Further, domain names registered with the DNS can be seized if a government serves a warrant.
On the other hand, the ENS uses the Ethereum (ETH) blockchain and is completely decentralized, meaning it does not require centralized approval and cannot be seized by the government. Currently, the ENS does not work on most browsers, although it does work on Opera, and users of the ENS can register .eth domain names.
Unstoppable Domains, which recently launched, also operates on top of the Ethereum (ETH) blockchain and offers .crypto domain names and has its own browser, offering a self-sufficient alternative for webmasters who would otherwise be censored.
It is unlikely that decentralized domain names like .ens or .crypto will ever truly compete with the DNS, but the important thing is these services provide an alternative, guaranteeing that websites which are prone to censorship will always have a venue where they will be visible.