How can the noticeable decrease of backlink numbers in the SISTRIX Toolbox for many domains on September 19, 2012 be explained?

If you analyze any domain in the SISTRIX Toolbox and look at the course of time of the links (menu entry “Development”), you can see a decrease of the graph from the 18th to the 19th of September in 2012. (You can see this as well on the course of the domains & hosts and IPs & networks)

Abgebildet ein Screenshot des Backlinkverlaufs der Domain zalando.de

A screenshot of the backlink course from zalando.de

Links That Are Not Found Anymore are Removed from the Evaluation Faster

We often heard feedback from users that say they want “fresher” links. We granted this wish and now remove links that are not found anymore from the evaluation quicker. We used to wait several months to see if the link might appear again, but now this process is shortened significantly. In a few cases this affects the total number of found links, but on average we do not see any significant movements in the evaluation. The deadline for this was September 19, 2012.