The phenomenon that people have claimed to observe is that Google temporarily reduces the page rank of new domains, placing them into what is referred to as its "sandbox", in an effort to counter the ways that search engine optimizers attempt to manipulate Google's page ranking to bring sites to the top, by creating lots of inbound links to a new web site from other web sites that they own before creating that web site. A "reverse sandbox" effect is also claimed to exist, whereby new pages with good content but without inbound links are temporarily increased in rank, much like the "New Releases" in a book store are displayed more prominently, to encourage organic building of the World Wide Web.
http://en.wikipedia.org/wiki/Sandbox_Effect