iMedia Connection’s Media Strategies Editor Jim Meskauskas wrote about social networks and viral marketing.  He offered four items that good viral marketing campaigns share:

• Entertainment: the marketing is entertaining.
• Utility: what is being marketed is something the reader can use.
• Palpable reward: the marketing provides instant gratification.
• Uniqueness: the marketing is like nothing the reader has ever seen.

He also describes the difference between frictionless and active viral marketing campaigns. Frictionless occurs when the audience spreads the good word via usage, such as Hotmail. Active viral marketing occurs when the audience spreads the word via actively recruiting non-audience members into the audience.

So, make a fun application that people will want to use, tell their friends about, and use.  Find a way to increase your brand awareness using from this tool, and potentially drive cross-over traffic to your website.