Document Inception Date
The search engine will learn the creation date of a document through crawling the document, submission of the document or when they first discover a link. Other techniques to determine the age of a document might be to look at the time stamp on the server or viewing the date that a domain was registered when the document was created. They will use this ‘inception date’ to score the document accordingly. Older documents should have a large number of back links while newer documents should have fewer. If a newer document has a spiky rate of growth in the number of back links then this may be seen as trying to SPAM the search engine and the score of the document might actually be lowered. In addition , The search engine “may determine the age of each of the documents in a results set, determine the average age of the documents, and modify the scores of the documents based on a difference between the document’s age and the average age”