On Saturday, July 23, 2005, 1:06:21 PM, Theo Dinter wrote:
On Sat, Jul 23, 2005 at 11:50:19AM -0700, Justin Mason wrote:
"Valuable (legitimate) domains are often paid for several years in advance, while doorway (illegitimate) domains rarely are used for more than a year. Therefore, the date when a domain expires in the future can be used as a factor in predicting the legitimacy of a domain and, thus, the documents associated therewith."
Domains registered for longer periods give the indication, true or not, that their owner is legitimate. Google uses a domain's length of registration when indexing and ranking a Web site for inclusion in their organic search results.
Unfortunately they're not actually checking for length of registration. Given the text in the first paragraph, they're looking for "expiration_date - NOW", not "expiration_date - registration_date", which I think is more useful.
My domain expiring in 6 months is not as useful as knowing that the domain has been registered for 10 years, imo.
Indeed. Google could also look at the content of sites over time and see how it changes, as with the Internet Archive:
An interesting and somewhat related behavior that we seem to be seeing is spammers taking over old (legitimate) domains that have expired, and using those names in their spams. Perhaps they're trying to defeat such historical content checkers. Fortunately the domain registration data generally show when a domain changes ownership as a new "Creation date", so that date remains useful for detecting freshly (re-)registered domains.
We and others find a very strong connection between domain age and spammyness in general. Most of the spammers' domains seem to be less than a month old, and most domains older than a year almost never seem to be used by criminal spam gangs. Their method of operation seems to require frequent shifting of domain names, etc.
Of course this answer varies depending on how one defines spam, but for spam gangs, who are probably the biggest, most destructive spammers, very fresh domains seem to be what they use.
Revealing that we know this should not help the spammers much since it's pretty widely known and when they abuse domains by spamming with them, those domains get blacklisted so they move on to others.
Jeff C. -- Don't harm innocent bystanders.