The rate or measurement of the number of back-links completely indexed in a specific period of time or the number of links de-indexed in that period of time is called Link Velocity. In other words, Link Velocity is the rate at which incoming links are added to your website. The chances of your website to achieve a top rank on search engine depend on the Link Velocity of your website.
But by adding low-quality network links or “spams” to gain a better and higher Link Velocity, you will end up being punished by search engines.
Domain Authority measures the power of a domain name. It is one of the search engine ranking components, and it is based on three factors: Age, Popularity and Size. The search engine helps users by providing them with a trustworthy website. With new website coming up every second and not lasting long, Domain Age sets apart a website due to its longevity and communicates to the search engine that the website is trustworthy. Similarly, when the owner of a website has maintained registration of a website continuously for a considerable period of time and was able to produce an increase in traffic, search engine deduce that the website is a trusted source and serves a purpose.