Why google not index my site yet?

Why google not index my site yet?: ":confused: I have done almost everything like submit sitemap to google. add my site link to signature and submit my site link to various directories. Now other two search engines yahoo and MSN have started to pick me up. However, it seems that google has not indexed my site although I have seen that the googlebot visited my site for many pages and continuously for several days. Any suggestion or comments on this?"