We all get spam, and I'm sure we all hate it. As a website publisher you may be tempted to use it to promote your site, I recommend against this. It is a bad idea all around and can get you in substantial trouble. Spam is not illegal everywhere yet, but in some areas it is, so not only could you face having your site shut down or civil action, but you could also face criminal action.
There is also quite a lot of confusion about what spam is. Simply put spam is any unsolicited email. It does not matter if that email went to 1 person or 1 million. It doesn't matter if that message advertises viagra or teddy bears. Spam is not defined by it's content, nor it's recipients. Spam is defined by its solicitation. Which means unless a person asked to be emailed then sending them anything would likely be a violation of your hosts spam policy, and possibly a violation of the law. All it takes is one person to complain to your host and they will likely shut your site down. Don't think people won't complain either, some people like yours truly take pleasure in shutting down spammers. There are also services like spamcop.net that automatic the investigation and reporting processes.
So does that mean you can't send anyone an email? No, plenty of people solicit emails, you just need to be able to recognize it. For instance if someone puts a link on their website that says "Contact us with suggestions and feedback" then they are soliciting emails. You could email them business proposals or anything else without worry of reprisal. If the link was worded "Contact us with suggestions and feedback about this site" and you sent them an email explaining how Viagra would help their personal life then that would be spam since they only solicited comments on their website.
So if you want to email someone make sure they solicit contact somewhere, if not then don't email them. If you just blindly email a proposal to email@example.com it can get you in trouble.