The average employee corresponds to other companies via e-mail over ten times a day
Ten times a day is a rather frequently, especially when you look at it over the span of the whole company. Even a small company with 5 people, you are sending out fifty e-mails a day. Now consider turning your email into a subtle marketing campaign. That is fifty potential advertisements a day, possibly more. Even if you are responding back and forth with the same people, each time they see the advertisement they are more likely to be interested. Think about how many times you see the same commercial on TV before you buy a product/service/etc.
So now the question is what can you do to turn your email into a marketing campaign.
The best way to go about it is to be as subtle as possible. People are very sensitive to spam now days, and if you make an e-mail full of images and HTML they are likely to be turned off quickly. My best recommendation is to use your signature, insert links to pages of your site where you have affiliate links, services, products, etc for sale. That way every time they read your e-mail they are likely to see them.
However – this is not a new idea, and you may already be doing this. There is a twist, and that is how you are labeling your links and additional text that you can put with it. Instead of just putting “Joes Plumbing” and linking it to your website, think of some aspect of your website that would interest people into going.
Change the link to “Why pay a plumber to do a five minute job?” and link to your page where you have some basic how-to’s. Further, you can add additional text to help increase the interest of every person who reads your e-mail. Every week put a different quote in the signature below your link, taken from an interesting part of your website. For example –
Why pay a plumber to do a five minute job? <--- Link to the site "Most drain clogs are simply the result of food backup in the drain, with the right house hold tools you can dislodge the backup..."
I try and avoid images in my signature, simply because a lot of email clients don’t show them by default to avoid possible virii and scripts. The result is your e-mail looks bad, and the information you want to convey through the image is lost.