Often distributed by email, or increasingly by download (e.g. widget mini applications), viral marketing strategies are usually designed for the web. and to be passed on to colleagues, friends or family.
Examples of viral content could be:
- educational or telling a story here
- news about a new product or update
- special offers, for example retail vouchers here
- big prize competitions, often based on consumers submitting their own content, as in this Canon NFL promotion
- funny videos or text, see this YouTube example, 12m views and counting....
- an addictive game
Often visually strong, viral marketing content aims to create immediate impact, ensuring it will get passed along. 
