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I have a customer who just bought a domain (and the full website) of a competitor and decided that they will no longer update the website purchased. The website of my client has a Domain Authority = 50 and DA of the website purchased is 45. Each of them was registered by different companies and are on different servers too.
The reason for my message is that by being registered by different companies and are in differrent servers I can use the site purchased as a way to make link building to the main website (one way link buiding only from the website purchased to the main website), but I can put the website purchased as a subdomain of the main website and agregate content to the main website.
In your opinion which would generate more benefits in terms of SEO to the main website? Links from the website purchased or put this website as a subdomain to the main website?