From what I understand buzz marketing is when people VOLUNTARILY talk about something that they're interested in. For example, if you find a video that you're interested in and pass it on to others, that would be an example of buzz marketing. Viral marketing is when you HAVE to pass something along in order to use it. A good example would be if you used a free email marketing service that requires you to add a link to their service with all of your emails. If you want to use that service, you have no choice but to tell others about it. I'm sure you guys know more about this then I do so please correct me if I'm wrong.