If you customize each email I don't think it should be perceived as spam. As others have said, do not make the email a blatant advertisement. You could conversationally introduce yourself and your services in the email. When you bring up your company in the messages, make it clear you are familiar with *their* companies by making comments and suggestions that are specific to each individual business.

David Frey recently wrote an article that includes some other ways to reach local businesses:
http://www.websitemarketingplan.com/Small_Businesses_Frey.htm


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