As the Marketing Manager for sitepoint and the group-wide search manager across 99designs, flippa, sitepoint, learnable etc...I'm deep in the mines of analysing our SERP's every day.
There has been no sudden slap, no loss of authority and no negative impact on Sitepoint. I track some 2000 keywords on a bi-weekly basis for Sitepoint. If anything, rankings are up recently and not down and traffic from Google over the last few days is actually about 5% above the 3 month average.
No need for panic. I'm sure that it's just a PR system hiccup. That being said, pagerank is nowhere near as relevant as it was 10 years ago. There are far more important factors at work.
Stay tuned for some big changes at Sitepoint in the next few weeks. There is something exciting happening here at our HQ