Everyone knows GoDaddy is pushing the multiple year domain registration:

Google recently filed United States Patent Application 20050071741. As part of that patent application, Google made apparent its efforts to wipe out search engine spam, stating:

‘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.

So to prove to everyone that your site is the real deal, register for more than one year and increase your chances of boosting your search ranking on Google.

I have read the doc beginning to end and honestly this is some of the driest garbage since my last RFC reading. The new GoDaddy sales technique, is one of the smartest examples of marketing seen from registars in some time. Then I have been around long enough to remember when longer domain names came out in 1999. That spawned a mad rush for hyphenated domain names that to me never really paid off for people. But a lot of domain names were sold.

What is described in the patent looks like a "method" rather than a new Google's algorythm add-on. As the patent's title implies, it's about a method to retrieve informations filtering them on an historical basis. "Google" name NEVER appears in patent contents. It seems spammers registers domains for just one year, often providing false admin and contact details. Domains registered for more that one year may get a higher score. The Patent does not refer to any historical data related to domain age: it seems to focus on domain expiration rather than domain creation. Therefore if your domain is 5 years old, and this would mean you're serious about it, you could even be penalized because you renew it yearly. When we all know that either or both can be collected at the same time.

While Information retrieval based on historical data is (or may be) a great method to leave spammers out of the door, there are some indicators Google actually uses to catch spammer sites.

1. Multiple domains with the same contents. Not uncommon to see many similar websites ranking high for certain keywords then disappear from index after a certain period of time (usually one month)
2. Google's ABUSE service. Based on users' input. Users can report a website they suspect it's spamming the search engine to Google abuse service. The website will be investigated (by a human) and, if it's caught on some spamming activities is banned.
3. Keyword Stuffing. Pages that present same keyword repeated over and over usually rank high for a short period of time then disappear from index. Keyword Stuffing infact is considered the most annoying spam practice.
4. Don't forget the so-called Sandbox effect (read about it on Google Sandbox effect)

Closing: I would have to question Godaddy scare tactics as a method for sales though it is proven to be effective. Logic would say Google would not use any single method like this to pollute a algorythm they have worked so hard to develope. If someone is registering a fresh domain name for the first time, it might be in their best interest to do so for more than one year. Or untill a history is established. Though logic would also say the same, to those search spam people after all the gain is great and the investment small.