I agree with CaptShady on the viral marketing, it's VERY effective.
One thing that you can do with all those silly little forwards we all seem to send...sponsor them!
I'll send out a funny to friends and family and at the top I will write, "This joke/touching story/fill in the blank is brought to you by Valley Virtual Assistants...assisting solo-preneurs with all of their marketing needs. Contact us at www.valleyva.net/special"
My family hated it at first. Why? I don't know...it's only one line, two tops of text...but I knew they were going to forward that email. My mother sends more forwards than real email.
I really didn't think many people would actually click on the link, but I figured it was worth a shot...by sending them to my home page (on a page name other than index) I was able to track how many people were coming thru the forwarded email and I was pleasantly suprised!