Read this article from The Marketing Mouse.

“As I have mentioned earlier, blog traffic can come from a few different places. This may be direct links to your site from other sites or Search engines. And we did establish that search engines however, offer the real key to high volume traffic numbers. Surfers rely on Google, Yahoo and MSN to help them find the sites that will provide them with the kind of information they are seeking. If your blog comes up early in those search engine results, you can expect a significant stream of traffic.”