Email marketing is a relatively low cost, high return on investment way for companies to get their messages to prospective and existing clients. While marketing budgets have been pared in 2009, the percentage of available budgets has increased more for email marketing than for any other promotional tactics.
By far the most effective email marketing campaigns use contact databases that are generated organically. By this I mean lists of contacts that are generated by people actively signing up to receive marketing communications from a specific company. Purchasing or otherwise acquiring a list of contacts where the recipients have not specifically opted in to receive marketing communications from that company is not a good idea, with the main reason being the likelihood of a campaign being flagged as spam.
Most of us are annoyed at the amount of spam communications we receive. It clutters our email inboxes and diverts our attention from messages we want to or should read. Due to the many complaints from their clients, major ISPs (Internet Service Providers) are using increasingly sophisticated methods to cut down on the amount of spam messages that pass through their servers. They pay close attention to clients who complain about receiving spam email from particular companies. When several complaints are received, it is possible that an ISP will block or blacklist the IP address of the server where the offending messages have originated. This unfortunately can have the very negative consequence of blocking other, more legitimate email traffic from that company from being received by the ISP's customers.
Major ISPs even look at the format of email messages to get a sense for which ones might be considered as spam, and which are desirable traffic. An email marketing campaign that has the content of the email as one large image is more likely to be flagged as spam than one where the content is coded in HTML as text and discrete images. A good ratio to target is for there to be roughly 80% images to 20% text in a given email. Granted it is more costly to construct such an email, but the resulting overall bounce rate (the percentage of non-delivered emails) is likely to be lower.
Care should also be taken to clean the email lists of addresses that are no longer valid. When an ISP sees too many emails going from a source to non-existing accounts, it looks too much like that company is using a shotgun approach trying to find legitimate email addresses.
Be sure to use "white hat" techniques when it comes to email marketing campaigns. Always provide a link in the email allowing recipients to opt-out of getting future mailings. Grow lists organically, with a good tactic being providing a sign-up check box on your website Contact Us form. Doing this can result in highly effective marketing campaigns with significant returns on investment.