tomshark - 3:17 pm on Oct 30, 2012 (gmt 0)
Google already discounted questionable links prior to Penguin, especially links that trigger the “unnatural link” filter, but Penguin has taken the discounting or discrediting of links to such a new level that Google feels obligated to provide webmasters with a tool to help clean up link profiles (perhaps Google even believes they have gone too far with their campaign to discredit questionable links).
In other words, G’s algorithm is not capable of detecting whether a link is natural or unnatural in all cases and is dependant on webmasters to keep track of all links to their website whether natural or unnatural and to take appropriate action to either cleanup their link profiles or not.
Google provides general guidelines on what links violate their Webmaster Guidelines rather than getting into specifics. Webmasters are left to interpret those guidelines as best they can so they can clean up their link profile appropriately, but many times webmasters are left wondering which links are ok and which ones need to be removed or disavowed. As you can see, interpretation of the guidelines is a tiny bit important.
G has highly developed and intelligent algos that can take a set of sites that are known to be spammy, slightly spammy, credible or highly credible and learn all the characteristics of those sites so they can be applied to very similar cases the algo identifies – known as a machine learning algorithm. Panda and Penguin involve machine learning algos which are accurate in many many cases but aren’t accurate in every case.
Google has Matt Cutt’s Webspam Team, or whatever they call themselves now, who make accurate interpretation and judgement about natural and unnatural links every time. The algo is designed to do the same job except on a much larger scale and therefore, without as much accuracy.
In May after Bing Webmaster Tools came out with their disavow link tool, Google Webmaster Tools provided a way to see when new links have been discovered by their algo. From within Google Webmaster Tools, go to “Links to Your Site” click on “Download latest links” and you get a spreadsheet of links with the date Google discovered them.