A text, video, graphic, PDF or sound file that accompanies an email message but is not included in the message itself. Attachments are not a good way to send email newsletters because many ISPs, email clients and individual email recipients do not allow attachments, because hackers use them to deliver viruses and other malicious code.

Combining Email Marketing with Other Types of Marketing
Whether you choose to do your marketing online or offline, one thing does not change. This is the concept that no single marketing strategy will be as effective as a combination of two or more marketing strategies.