There are a few important metrics you should familiarize yourself with when selecting domains for domain parking.
Alexa rank measures the popularity of millions of websites, a website with a rank of 1 being the most popular and having the most traffic. Registering domains with an Alexa rank and no backlinks suggests the traffic mostly derives from a user directly typing the URL into their browser navigation bar. (Type in traffic)
The Alexa rank is estimated based upon the browsing behavior of millions of internet users using one of over 25,000 different browser extensions and of users and sites that install an Alexa script to certify their metrics.
Like Alexa, Similar Web measures the popularity of millions of websites, a website with a rank of 1 being the most popular and having the most traffic. Registering domains with a Similar Web rank and no backlinks suggests the traffic mostly derives from a user directly typing the URL into their browser navigation bar. (Type in traffic).
A Similar Web rank is calculated from data captured via apps, browser plug-ins, desktop extensions, data from global and local Internet Service Providers (ISPs)and data measured from traffic from selected websites.
Seo MOZ Domain Authority (DA)
Domain Authority (DA) is a search engine ranking score that predicts how likely a website is to rank in search engine result pages (SERPs). Domain Authority scores range from one to 100, with higher scores corresponding to greater likelihood of ranking. The best traffic domains for parking purposes are those with a DA close to or greater than 20.
When an expired domain has a high DA, it is an indication of the quality of links, linking into the root domain vs other domains of a similar category.
Example of the domain Hotels.com vs other domains in the same category. Source: Moz.com https://moz.com/domain-analysis?site=hotels.com
Number of Equity links to the domain/url
Equity links are links that pass value from one page to another.
Page Authority, Domain Authority, Page Rank and the age of the domain (when it was first registered) help calculate the equity value.
Number of and QUALITY of backlinks.
Domains with a high number of quality backlinks are preferable. But you must calculate the cost of these domains. “taste” (test) many domains with lower quality backlinks or target only those with the best backlink profile?
An unusually high number of backlinks can suggest the domain may have been compromised in the past, been used for spam, malware etc.
To measure the relative quality of a domain’s backlink profile, the two largest backlink monitoring services are Majestic SEO and AHrefs. Each has their own method to measure the number and quality of backlinks.
Domain Rating (Ahrefs). 1-100. The strength of a target domain’s backlink profile vs comparable others.
Trust Flow (TF) & Citation Flow (CF) (Majestic SEO)
TF – 0-100. How trustworthy a page (or previous page was) based on how other trustworthy sites link to their neighboring sites. For example, are the sites linking to one another in the same category/niche? Are they trusted sites?
CF – 0-100. Estimates how influential a URL might be based on how many sites link to it.
Ideally you should be looking at registering domains with a high Trust Flow. Trust Flow should generally be over 10 and ideally over 15 with a CF/TF ratio of 2 to 1 (CF ÷ TF).
That is if a domain has a TF of 20, the CF should be 10 or thereabouts.
Date of domain registration
Older domains are typically more valuable and should be prioritized over domains registered in the past 3-5 years. Be careful of domains registered in the last 3-5 years with unusually high numbers of backlinks. It is common for newly registered domains to be spammed for SEO (search engine optimization) purposes.