There are so many scammy domains out there with high page ranks, which people have purchased for large amounts of money, only to find out that the domain was worthless. Most people use Page Rank to filter; some use Moz Domain Authority, while others use Majestic Seo Trust Flow. However, one thing that you need to know is that every single metric can be manipulated. It is easier to manipulate some (DA) and tougher to manipulate others (TF), but relying on a single metric is a fallacy. Domain Age- Search engines prefer older domains since older domains are more trustworthy. If the expired domain has not been dropped, it could retain its age in the eyes of the search engines. The domain age can be found from the WhoIs details for that domain. This is based on the date on which the domain was first registered. But this is not necessarily the date that the search engines use. If a domain has been registered on a certain date, but a website does not yet exist at the domain, then the search engines may not take that registered date as the birthdate of the domain. In this case they would consider the date when the website was first crawled. You can estimate this date from the WayBack Machine. Page Rank - Page Rank is the default metric most people use to judge the value of a domain. Note that for the last few years Google has been saying that the Toolbar Page Rank will no longer be updated. So over time this number is going to be useless.What most people do not know is that the PR that is shown on the toolbar is not the PR that Google uses internally. Internally the page rank is being continuously calculated and used to rank websites in the search results. However, Google only pushes out this data to the toolbar once a year (and may not in the future). Hence this data tends to be old and quite useless to base decisions on. The PR can also be easily faked by forwarding a domain to any website with high PR. â€‹Moz Metrics - Domain Authority (DA) is a metric between 0 and 100 that predicts how well a website will perform in SERPs. DA can be used to compare one domain against another. Page Authority (PA) is a metric that denotes the chance of a specific page to rank in the SERPs. This is similar to the DA for the domain - however it is a metric for the home page of the website. In an ideal situation these two values should be very similar to each other. DA/PA tend to be very popular metrics to gauge the value of a domain. Unfortunately they are also extremely easy to manipulate. For some reason, the other Moz metrics like Moz Rank and Trust Rank that are equally good, have not found popularity with domainers. Majestic SEO Metrics - Trust Flow and Citation Flow have gained in popularity over the last few years. While the Citation Flow is a measure like Page Rank and is very easy to manipulate, the Trust Flow is a much tougher metric to manipulate and has therefore become the default metric that is looked at first. However, an even better metric that is harder to manipulate is theratio between the Trust Flow and Citation Flow. Most real domains will have a TF/CF of slightly more than 1, while scammy domains have a ratio much below 1. SEMrush Metrics - SEMrush provides SERP data for domains. This data essentially tells you if the domain currently ranks for any keywords and is a good estimator of the traffic you can expect from it. They offer the number of keywords, monthly organic traffic volume and cost (based on keyword cpc and volume) SimilarWeb Metrics - SimilarWeb provides metrics for domain traffic and its rank compared to other domains in the world, and in its niche. While the traffic numbers might be a little off, it is a great way to compare between two domains. Compete Metrics Compete provides the approximate number of U.S. visitors to the top million web sites. They compute this data directly from ISPs and application service providers. Tip: If you are looking for US based traffic the Compete traffic data is worth looking at. Alexa Metrics - Alexa maintains ranking data on all websites in the world. The ranking algorithm is based on the total amount of traffic over the last three months. They take data from a sample population and build the rankings off that. The rankings are not accurate enough as the sample population is biased (data is taken mostly from those with the toolbar installed). Also they can be easily manipulated by increasing the number of visits to a domain after installing the toolbar. However, since Alexa rankings have been there for a long time, they are quite popular among users. Back Link Data - Back links determine the page rank of the domain and therefore checking the back links to a domain is paramount in determining its true value. However mere back link counts are not enough. Many domains will have loads of back links that will disappear soon after you purchase them. The trick is to find out which back links look like they will stay once the domain has been purchased. You can check the back links from Google, Moz, Majestic SEO and Ahrefs. Google would obviously be our first choice. However, Google does not show very accurate data on the back links. Sometimes it may show no links at all. Therefore, although you ought give higher priority to the links you find through the Google link operator, you should also check the back links from Moz, Majestic SEO and Ahrefs. Ideally you should do a check using all three. Google Penalties - One important check to make is whether Google has indexed any pages from the domain. While some domains (namely in GoDaddy auctions) will have a single page indexed, you should be wary of domains that have zero pages indexed. This may be due to a manual or algorithmic penalty on the domain due to black hat seo tactics. It?s also possible that the domain expired a long time ago and the site has been completely de-indexed from Google. Domain industry/sector - Most often people buy expired domains for a specific industry or sector. It is therefore useful to know what kind of website existed on the domain before you purchase it. It could be a site that does not fit into the category or industry that you want. The best way to check this is to go to the WayBack Machine and check the different versions of the domain since it was first online. Also check the Topical Categories and see whether the links to the domain are from the same niche as shown on the Wayback machine Tip: Google gives contextual links more weightage. If you are buying an expired domain for linking to your money site, then definitely look for a domain from the same sector/industry Social Stats - Not sure how much social sharing affects SEO and domain rankings. However, if a domain has been shared across multiple networks it might be a sign of legitimacy for the search engines. Of course, don't get carried away by a domain that has a very large social count number, as these are extremely easy to fake.