Disadvantages of Viral Marketing

Brand Dilution
It depends upon people not versed in your brand to do the "selling" for you. It is important to carefully bring a message that makes your communication brandness.

Association with unknown groups
Viral marketing's strength is its potential to spread exponentially from person to person. During this process, it is possible that the message could wind up in the hands of and passed on by someone who would rather not be associated with. The only way to partially counter this is to ahead of time define an dlimit what information to make available for viral marketing.

Spam Threats
Viral marketing is done poorly, it can lead to large-scale spam issues. Flames may result, leading to damage to the advetiser's reputation. If friend's receiving an unsolicited commercial email can weaken his or her replationship with the person who sent it. This can lead to the recipient of the email dropping a friend and becoming angry with the marketer for sending an unsolicited message. In McDonald case, there are many pop-up ads on the yahoo, msn etc websites. It will lead to the recipient becoming angry and trouble with the marketer for some unsolicited message.