Google's search engine secret sauce, the PageRank algorithm, finally gets an update after 6 months since its last update. Normally, PageRank updates every 3 months. There have been reports about a massive drop in sites that are widely known to be selling text links which Google identifies as manipulating search engine results. There have also been reports that YouTube's PageRank drops to 3.
Side note: You will now receive a confirmation if you submit spam or paid links report in Webmaster Tools which says:
Thank you for submitting a spam report for this site: [submitted URL]
We take the quality of our results very seriously, and we thoroughly investigate every report of deceptive practices and take appropriate action when we uncover genuine abuse. In especially egregious cases, we will remove spammy websites from our index immediately, so they don't show up in search results at all. At a minimum, we'll use the data from each spam report to improve our site ranking and filtering algorithms, which, over time, should increase the quality of our results.
We appreciate your taking the time to help us improve our service for your fellow users around the world. By helping us eliminate spam, you're saving millions of people time, effort and energy.