Spamming, especially to Internet centric companies will actually negatively effect your company. Spammers and their providers tend to be 'blackholed'. When ISPs receive spam from a certain address, many will disallow their users to receive mail from you to help filter. This means that people who would be interested in your service may not be able to communicate with you. Harvesting e-mail addresses for spamming is considered bad form.
Many Internet users consider spam an invasion of their privacy.
People value their privacy, and if you are invading it, they are likely to not only not buy from you, but also tell others not to buy from you. In most cases you will loose your Internet account with the ISP you spam from. Most ISPs now have an Acceptable Use Policy and Privacy Policy that you agreed to when you signed up. Very few providers will allow you to spam because they are likely to be shut off by their provider for your spamming. While spam seems to cost very little or nothing to send, you are actually passing the cost to the receiver.