I agree with BK42. Word of mouth is the absolute most rock solid form of advertising. That is why social media sites are becoming vastly more popular and the majority of the websites which are popping up online are WordPress blogs. Unless you have been living underneath a rock everyone knows Facebook, LinkedIn, etc.
You just do not want to do direct, in your face advertising to your end users because it is a fact that we do not like to be flooded with "buy this or die" types of advertising anymore. In that sense we are evolving.