I received this from Perry Marshall and I am including it in its entirety below.
This is very good advice. You don't want all of your eggs in organic results or in adwords, and I would say you'd want to add off-line sources as possible too like telling everyone you know about your blog which has an ad on it to your site and specifically asking people to go to your site. Don't forget to use social networking sites and blogs all over the net.
---------- Forwarded message ----------
Just got this email from a customer:
"I am reading through your ebook at the moment.
My most common search terms are already #1 ranked in
Google (regular search results). Should I also advertise in
ADWORDS for those same terms? Would it help me
anymore or is it just a waste of money?"
You should do both. Sure, free is always a great deal, but
you should still buy advertising as long as it will give you an
acceptable return on investment. It's kind of like owning stocks--
some stuff gets you 17% interest this year, other stuff makes
you 2-3%, but you dollar cost average it out and do OK.
Plus, people who depend on free search engine listings
are *extremely* vulnerable to Google's whims, and if
you read much on this subject, Google's been just
nasty these last few months. One day you're #1
and the next day you're not even in the top 1000 -
literally, that's really happening. Don't ever rely
on just one thing.
Finally, one of the best things about AdWords is that
you have complete control and you can test ideas
before you roll them out. That's a HUGE advantage
which is not possible with free search engine traffic.