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Many people configure their computer or router to use a specific DNS server that they prefer (such as Google DNS which is found at 8.8.8.8). The expectation is that the server at 8.8.8.8 provides your DNS services, but that isn't what really happens. If it did, that server would be swamped with requests. Instead, it hands your request off to another server that's part of a large group of servers that it controls. By doing this, no one server will be completely overwhelmed with requests.
The data that's reported here shows the identity of the server that actually processes your requests. You can verify that it's being run by an organization that you trust. We also check the reputation of each server that we report to see if it has been flagged by people for doing questionable things.
This also explains why if you check your DNS server multiple times using this service you'll often receive different IP addresses. This happens because each IP address represents a different server in the "group".