SANDBOX

The sandbox is essentially a filter that was created by Google to avoid spamming of search results by unscrupulous webmasters. This is where sites are kept till they get mature enough to be included in the top rankings for a particular keyword. Before the sandbox was created, most new sites could rank pretty quickly, which allowed certain "black hat" professionals to make a quick buck by ranking a new site on the top of Google's index for a very competitive keyword, and then cashing out before Google caught up with their spam technique.