It is my understanding that if you send an email that has something worth passing on. Not this "send to 10 people" stuff, but a funny story or something like that then the is the chance that the email will go viral if the receiver(s) pass the story on.
Viral marketing is generally something that people willingly pass around. Email marketing is generally something that a marketeer uses to entice an end user. They are very different. Look up 'viral marketing' and 'email marketing' on wikipedia and you will have a full answer.
__________________
Leadbolt.com - Better than Adsense
Email Marketing is ranked as the #1 effective way to market your services/products in terms of ROI. Viral Marketing is to create something viral that people are willing to pass alone.
__________________ World's leading Please login or register to view this content. Registration is FREE . All free now.
Viral marketing is medium agnostic. That is it is a concept of getting a message to self propogate itself till it reaches a critical mass, after which it grows of its own due to the sheer volume promoting it (goes viral). The initiator then has no control or role to play in the promotion part after that.
Email marketing is a specific medium used for marketing and sometimes an email message can go viral too. When it does, you can categorize it as viral marketing but usually it will be rare.