PageRank update going on the blog My partner Data Communication, a drop from PR2 to PR0 in the second week in January 2009. In the first week in February 2009 Data Communication PageRank again increase to PR2 and drop back to PR0 at end of February 2009.
PageRank update is not only happening on the blog Data Communication but also on the website / blog the other. My friend in the discussion forum also experiencing the same thing, drop the PageRank from PR4 to PR0.
Currently, Google PageRank update often do with new technology they use and from the results that I watched through the Google webmaster tools, and bar tools, this update is done every 2 weeks. Google PageRank update to select whether the website is in the appropriate search engines and also to block websites that occupy the top positions in search engines in a way not normal (the hacking) and Google said "he was lucky" because it is in the top position in search engines.
From this it can be concluded that the Google PageRank update every 2 weeks. This is the beginning of My analysis, it is possible that the PageRank update schedule can be changed so that the PageRank to be more stable and only Google team understands this problem.