My temporary email domain, my_temp_email1.temp_email_domain.com, is not the only one of its kind. The 2nd-level domains associated with it are unique, consisting of 20-30 different pieces, all within the com zone.

It's intriguing to consider where these domains come from. Surely the owner of the service couldn't have possibly purchased them all.

These domain services offer premium domains that come at a high cost, but volume discounts can be provided as well. For example, purchasing 60 domains in the com zone can amount to approximately $400-600 per year. While this may seem expensive, it's a small price to pay for a personal hobby or an advertising service. Fortunately, there are also cheaper options available in different zones.

1. The cost of programming work alone exceeds that of buying a domain name, and web hosting prices for popular hosting companies are not exactly cheap in comparison to domains.

2. It's unnecessary to purchase expensive domains in high-cost zones if you're simply looking for email functionality. Any domain name would suffice in this case, so opting for a cheaper option is more suitable.

3. In my experience over 15 years, I've accumulated 5 unnecessary domains. If someone is entrenched in the web industry, it's likely they've amassed a similar number of unused domains.

4. Additionally, discounts are available for domains that don't carry a high price tag.

The origin of these unique second-level domains is still a matter of speculation. It is unlikely that the owner of the service individually purchased or registered all of them due to their large number and uniqueness. It is possible that the domains were acquired through bulk purchases or partnerships with domain providers. Alternatively, they may have been generated using automated algorithms or custom software specifically designed for creating unique domain names. Without specific information from the owner or a deeper investigation, the exact method of acquiring or generating these domains remains unknown.

It is unlikely that the owner of the service purchased each domain individually, considering the large number and uniqueness involved. One potential explanation is the use of domain generation algorithms to create these domains systematically. These algorithms generate random combinations of characters and test their availability for registration.

Alternatively, the owner may have partnered with domain registrars or acquired the domains from a secondary market. It's also possible that they used a combination of these methods, leveraging both automated generation and strategic acquisitions. Without specific information from the owner, it's challenging to determine the precise process behind the creation of these domains.