Updating Links: An SEO Red Flag?
Following on the heels of Eric Lander's NoFollow: An SEO Red Flag?, I thought I'd pose the question of whether updating inbound links may also be a red flag.
Google uses inbound links to assess the value of content, but it wants those links created naturally. Don't get me wrong. Naturally doesn't necessarily preclude a marketing effort, but it does mean that the person that created the link was free to choose what URL and anchor text to use. Overtly manipulating those two items is entirely unnatural and I would think Google would want to devalue the impact of such behavior.
Deciding What Is Unnatural
So what might this mean? Well, if Google detects that the anchor text of a link is updated 30 days after the link first went live, I'd say that's pretty unnatural. But that's not good enough because, despite being rare, some people do go back and edit old content. So lets add another layer that includes checking the number of links on different sites that all point to the same site that within a short period have their anchor text updated. That combination of variables seems like a pretty good indicator that there's an active SEO effort in the works.
The trick here is determining the threshold where updated links reveals a concerted effort rather than just the natural edits people make. I don't think figuring out such a threshold would be too difficult. I'm sure the Google spam team could come up with that measure along with a few refinements during their lunch break. And I suspect Google already has the storage capacity to store previous link data to compare to current link data.
OK. The tinfoil hat is coming off now, but I would be interested in hearing what others have to say about this theory.