Page Rank Update is over 20 days late as of today. Google usually update’s it’s page rank approximately every three months give or take a few days to keep people guessing however rarely this late.
Last Pagerank update was called the Mayday update but it happened end of April. Some sites dropped ranking and traffic, and some gained ranking and traffic. Mayday update was somewhat big because it seems that it was targeting paid links and artificial links.
According to Google’s link scheme guidelines, you are not supposed to buy links other than for purpose of advertising and in that case you are supposed to put nofollow on it or prevent pagerank juice with JavaScript that way search engines know that is an advertising link and not editorial links.
But m any webmasters and SEOs continue to violate this guidelines because they find it hard to get links that are in accordance of Google guidelines. Or they lack good link building strategy and skills so they buy links.

Google has been at war with link brokers. They even dropped a few of them, such as Text Link Ads, from their SERP a few years ago in order to make an example of them to rest of the link brokers. Also I recently noticed, if you search for “paid links” or “text links” you will no longer see any PPC ads by any text link brokers whereas a couple months PPC ads were visible. It seems that Google is willing to go that far, in its war with text link sellers.
Up to this point, Google’s search quality team has been optimizing their algorithm to bring the most relevant search results and avoiding spammed websites as much as possible. And Google’s web spam team, has been in charge of writing web filters in order detect spam if it bypasses the algorithm written by the search quality team. They also do a ton of human auditing and manual work. About 3 months ago Matt Cutts, head of Google’s webspam team, call out for others to report webspam to Google. He singled out “paid links” and Google even created a separate spam report form just for reporting paid links;
But Google hasn’t stopped there. Mayday update, effected the sites that bought links heavily but they are not stopping there either. As I mentioned earlier, pagerank update is unusually late, and many SEOs suspect that Google is up to something big. And from latest patterns of Google’s behaviors and algorithm changes, it seems that paid links are on top of Google’s search quality team and web spam team agenda.
So if you are buying links, be prepared for consequences and don’t buy links unless you absolutely have to and know what you are doing.