The home page alone of my site was delisted from google yesterday for no apparent reason. I haven't created any backlink to this site in weeks. It was ranked on the 3 spot and now is nowhere to be seen. I think it was a manual penalty cuz when i search for the domain itself, the home page is not listed anymore. I have two guesses about this problem. Negative seo from a competitor website is the first one. The second one is more of a conspiracy theory guess. My site that got delisted by G is a tutorial website. It competes with big companies that offer a service ( Companies like microsoft, yahoo etc ). The top 9 results listed those companies, being my site the only one that did not fit the bill untill yesterday. Do you guys think that G delisted it to favor those companies? I'm noticing more and more big companies taking over the top ten results after penguin and panda ago updates. Small to medium sized tutorial sites are falling like rocks lately.