Hi Ging,
You mean just regular advertising? Sure thats another important way to get traffic. You should not just rely on Search Engines because they can change algos or drop you.
I do lots of Guerilla marketing (low cost advertising) including PPC with Google and Overture, Adbrite and BlogAds. One of my new clients is another great option.
www.text-link-ads.com. I have not tried them yet but plan to.
Plus of course having an affiliate program is another way to advertise on lots of sites
