I wish I had the time and inclination to sort out all of my uniques, but for this discussion I'll have to include AdWords. I'll guestimate they bring me less than 3%.

I have three years of sweat capital into my site and I'm averaging 6,000 to 8,000 uniques a month. I know that most of it comes from two sources, word of mouth and hard work (relatively speaking), also known as SEO. My site languished for 6 years, but that seems to lend some value as an authority (good for SEO). Extensive sitewide SEO has helped tremendously. A word of caution: Don't do anything all at once, especially sitewide. My growth is natural, closely following my learning curve. Link exchanges have helped. I hand-picked several type of sites where I felt I could benefit from a link. And I watched those just like I watched my keywords. I link to relevant sites that have a good chance of bringing me a qualified lead. 1 of 100 link requests will get my attention. Note also that I build my sites for my visitors, not for SE's, but I adhere to common standards and known good practices. It follows that the SE's appreciate and list a site that visitors can use and enjoy. It's a great source of uniques.

Some of the things you mentioned, especially in the list of exclusions, cannot be written off so easily. Why? Residual growth. And I can't think of any method to track that growth. Say that I do targeted newspaper ads in an area, then I can reasonably track those uniques. But when I leave the area, it would likely be word of mouth and good SEO that continues to drive my stats. I'm not about to discount those unique visits.

hi SSG

Thanks for that detailed reponse,

Regarding PPC/newspapers et al, I only excluded them cos off cost.

Well funded businesses naturally will make good use of those sources, A skint(broke) chap in his bedroom might be better advised to stick to SEO :-)