[spyrosk]

The problem is that all of these techniques are based on speculation and/or empirical data, but without solid measurements, especially since google's ranking system is a black box. Personally I have encountered 2 opposing opinions on this subject, one suggesting that google does take the duration of the registered domain under consideration, based on some patent that google had filed about it's ranking system, and the other one was from some supposed employee who claimed it didn't, due to the fact that some registrars withhold this information and thus no comparison could be made between them and domains on those that publicized it.

[gojomo]

I can't claim to know Google's actual procedures, but if you have a system with many thousands of candidate signals, and you train it to achieve certain 'quality' rankings via a largely automated process, it's possible that even the designers of the system would not know how every signal, in every combination, affects the rankings -- without researching very specific conjectures one at a time.

To wildly hypothesize, what if length-of-registration tends to indicate more-beloved results in most .COM domains, but has no impact on .ORG and .GOV domains, and actually indicates less-beloved results in .COM domains that consist of generic common words (those loved by professional domainers who then lengthen their registrations strategically)? A learning system could discover these conditional relationships over time -- but they'd resist easy explanation by a employee summarizing factors via informal channels.