The plot thickened last month when Google launched Search plus Your World. Jack Menzel, director of product management for Google Search, explained that now Google+ users would be able to “search across information that is private and only shared to you, not just the public web.” According to Ian Lurie from the blog Conversation Marketing, in Search plus Your World, search results that received a lot of +1s tend to show up higher in results.
Google has come out and described the purpose of a +1, but hasn’t necessarily explained the direct effect a +1 has on search ranking. Here’s a breakdown of what we currently know.