Because SEO and the techniques of web search are constantly changing, Matt Cutts' advice can sometimes be outdated. In the video below, Cutts gives updated answers to outdated questions. In May 2010, he explained how twitter didn't effect Google web rankings; however, this changed in 2011 when Google started using information on twitter to determine the reputation of a person or business. Another small yet important change in Google's search operation revolves around safe search. In previous years, Google would not return web results from pages that were blocked from being crawled. Because many of these sites were .org and .gov pages, Google now uses other factors to determine whether or not a website is reputable enough to be returned in a safe search result.