What is called The Sandbox in search engine?

It's thought that Google has implemented a time penalty for new links and web sites before completely marking the index, based on the presumption that 100,000-page websites can't be created in overnight. Certain web sites, or links to them, are "sandboxed" for a period of time previous to they are given full rank in the index. Speculation is that only a set of competitive keywords (the ones that are manipulated the most) are sandboxed. A drifting legend in the search engine world, the way of life of the Sandbox has been debated, and is yet to be long-established by Google.