I'm the an owner of an youtube channel with over 18,000 subscribers and over 1400 friends.
http://www.youtube.com/user/uriniass
I will post a bulletin once, it will contain your link to your website or product and a SHORT message. I will send you a screen shot as proof.
(whenever people send bulletins on YouTube, all of your friends and subscribers will see it on their youtube Homepages) so that means over 17,000 people will see your advertisement.
You can learn more about YouTube Bulletins here http://www.google.com/support/youtube/bin/answer.py?&answer=178035