I have to admit, I used to be skeptical of Twitter. I also didn't see the integration between Twitter and Facebook with e-mail. But then I started to realize these channels could be very useful to extend the reach of my e-mail programs: We placed links to our e-mails on the social networking sites. And guess what? We saw a great lift in response.

According to a recent survey from Forrester Research, 77 percent of consumers said they receive e-mail from at least one retail company. With the industry so immersed in the channel — on average, the retailers surveyed have been sending e-mail for seven years — it's easy to see how a company's e-mail can get lost in the crowd. To succeed in today's e-mail marketing environment, you need to retain the customers you already have while differentiating yourself from your competition to recruit new ones.

This week I discuss mistakes seven through 12 in my list of the 12 common e-mail marketing mistakes made by today's e-mail marketers.