Because it's about time
When in comes to doing SEO for Google, one thing is certain; youd better know about backlinks. Given the fact that the core algorithm is based largely on ranking and detecting spam via links, it is certainly an area to be familiar with.
A while ago there was a re-release of a Google patent on temporal ranking factors which really was a watershed back in 2005 when it first came out, as were subsequent related patents. Analyzing the recent (re-released) publication for new anomalies gave life to the thought that it would be interesting to highlight a few areas as a bit of a refresher course.
For this post I am merely going to address the implications of temporal factors on link building programs.
The basics of historical factors
Just because a web page is 10 years old, doesnt mean it is still relevant. It also doesnt ensure that it is. In some situations fresh content can be more relevant than older content. The discovery data can be used to re-rank a document in a positive or negative manner
Search engines, (such as Google) can use temporal data to analyze link profiles for anomalies based on discovery, (inception) dates;
it may be assumed that a document with a fairly recent inception date will not have a significant number of links from other documents
And can be used for Spam detection;
While a spiky rate of growth in the number of back links may be a factor used by search engine to score documents, it may also signal an attempt to spam search engine. Accordingly, in this situation, search engine may actually lower the score of a document(s) to reduce the effect of spamming.
Thus inception dates and historical data can be used for link velocity analysis.