There's confusion about what the Google Sandbox actually is and whether it really exists, but most search engine optimizers have come to agree that it's a mechanism used by Google to reduce the importance of new websites. Why would they do this? Google's priority is to provide quality search results to its customers, and one of the biggest threats to their ability to do this comes from spammers. Spammers frequently register hundreds or thousands of domains, fill them with content duplicated from legitimate websites, and create a network of backlinks designed to propel a brand new spam site to the top of the index.