How does a kingdom built on red meat convince its loyal subjects to try chicken for a change?  For Burger King, the answer involved a flamboyant, apartment-dwelling chicken and an always-on web cam. In an effort to sell a greater number of chicken sandwiches, the fast-food chain launched Subservient Chicken in April 2004. Visitors to the site could instruct the chicken to do their bidding, and the pure insanity of the interactive effort gave it tremendous viral strength. Burger King was suddenly synonymous with chicken, and they reported an improvement in their chicken sandwich sales.

While certainly not the first viral campaign, the Subservient Chicken still stands as one of the most notable viral efforts. 

Why it's important:

• The combination of video and interactivity creates a heightened level of user engagement.
• This combination added to creativity can turn an interesting campaign into a viral hit. 
• Sometimes turning consumers into evangelists has a greater impact than telling people they should be customers.