The Sandbox (a.k.a. Sandboxing or the sandbox effect or the Google penalty) is a name given to an observation about the way Google ranks web pages in its index. It is the subject of much debate—its existence has been written about since 2004 but not confirmed, with several statements to the contrary. Sandbox effect According to the sandbox effect, links which may normally be weighted by Google's ranking algorithm, not least improving the position of a webpage in Google's index, may be subjected to filtering to prevent their having a full impact. Some observations have suggested that two important factors for causing this filter to come into play are the active age of a domain, and the competitiveness of the keywords used in links. Active age of a domain should not be confused with the date of registration on a domain's WHO IS record, but instead refers to the time when Google first indexed pages on the domain. Keyword competitiveness refers to the search frequency of a word on Google search, with observation suggesting that the higher the search frequency of a word, the increasing likelihood that the sandbox filter effect will come into play. While the presence of the Google Sandbox has been long debated, Google has made no abject disclosure on the matter. However, as the sandbox effect almost certainly refers to a set of filters in play for anti-spam purposes, it is unlikely Google would ever provide details on the matter.
Why would Google suspend ranking of new websites? Actually, Sandbox does not exist, it never existed…. None of the any Google representatives ever confirmed the existence of sandbox. You just ignore this effect..... fall down in rankings, disappearance of websites from search results is not related to sandbox in any way.
Because a 5 day old site could use black hat methods to get to page 1. ex. Use software to get 10,000 blacklinks overnight.