Rosalind - 12:24 pm on Sep 29, 2004 (gmt 0)

I've always assumed that the sandbox was a symptom of spam rather than a deliberate algorithmic choice. Here's my theory:

Sites will not be put in the full index without sufficient quality inbounds. The index has grown, so perhaps the number of these inbound links required has grown. A lot of scraper sites provide inbound links, plentiful yet individually insignificant. It takes a while for these scraper sites to pick up on a new site. New pages will have the benefit of the rest of the site's anchor text, plus any scraper site anchor text linking in, whilst new domains will have neither until they get into the full index. That's your sandbox.