There are no specific criteria for measuring the quality of a TLD. Taking the data of the PuntuEUS Observatory as the basis, we have taken the following criteria into consideration when gauging the quality of TLDs.

Domain density: The contribution made by each domain to the Internet. To measure this, the average number of documents in the websites of each domain were measured.  The result clearly shows that among the predominant TLDs in the Basque Country the .EUS domain is the one that makes the biggest content contribution towards the Internet. So it can be said that the .EUS websites post a lot of content thus making a big contribution towards the Internet. That is important in our case because a large proportion of that content is posted in Basque as far as the .EUS domain is concerned.

Number of active domains: The number of active domains among the registered domains. Many domains are registered defensively, in other words, to prevent anyone else registering the same name, and then they are not subsequently activated. Out of the domains that a TLD has registered, it is important for as many as possible to be active. This criterion can be measured in the case of all TLDs and that is why a comparison is provided below. It can be seen that the .com is the most used among the main TLDs present in the Basque Country, both in terms of the number of registrations and also in terms of the domains that are active. At the other extreme would be the .biz TLD; most of the .biz domains registered are reckoned to be defensively registered ones. Among the main TLDs in the Basque Country, after .com, .EUS is the domain that has the most active domains, 58%. That means that the use of the .EUS domain is high among the registrars.