anallawalla - 9:10 am on Oct 29, 2004 (gmt 0)

A brand-new site will also be greybarred, so you need to check the Wayback Machine and other search engines for signs of age, e.g. 9-12 months, in which case the grey bar suggests a removal from the index.

It isn't conclusive evidence. Some sites are never submitted or linked to from anywhere. I know a 2-yo personal site meant only for family and it shows no PR and can't be found on the main SEs.