I have come across many bloggers who woke up on a fine morning to mourn about a sudden drop in their levels of liquid, er.. what’s it? Mercury? No, it is Google PageRank (PR). They have all the reason to mourn, as they are paid for blogging depending on their PR. The higher the PR, the more they earn from blogging. Once they are comfortable with their incomes, there is the sudden bolt from the blue! The PR drop! If PR is "0", buyers of links are the least interested in hiring you! The income = "0". After some time of low income and PR="0", you find it again back to normal. You regain part of the lost steam or juice! Google says, "Help us maintain the quality of Google search results". And Google adds, "Unfortunately, not all websites have users' best interests at heart. Some site owners attempt to "buy PageRank™" in the form of paid links to their sites. Buying links to improve PageRank violates our quality guidelines."
I quote from Google's site, "Google uses a number of methods to detect paid links, including algorithmic techniques. We also welcome information from our users. If you know of a site that buys or sells links, please tell us by filling out the fields below. We'll investigate your submissions, and we'll use your data to improve our algorithmic detection of paid links." Click here to read the original Google stuff.
Have any questions on Google PageRank, or how you can earn from blogging without losing sleep or PR? Post your questions and I will reply them, of course quoting Google and other well-learned professionals.