Why is user-generated advertising so powerful?

User generated advertising is content which is made by non-professionals. For example: social networking sites, YouTube and Wikipedia. These online platforms allow you to create shareable content which can be viewed by anyone. Within Starbucks iconic white cup decoration idea, people have incorporated user-generated advertising which infers that people have taken pictures or  reviews in any conceivable way to showcase the decorative cup event.
User-generated advertising is extremely powerful for various reasons such as being cost effective, more accessible, shareable content and it provides exposure. User generated advertising is cost effective as we don't have to pay to get access to it. Furthermore, as being the pro-sumer we are building  awareness for specific events, commemorative items or anything we are trying to demonstrate. By doing this, we can be rewarded money in the long run which also allows you to profit. This is cost effective as you showcasing this to a wider audience  instead of using outdated traditional media which are more time consuming and permits you to use a lot of money.
  Moreover, user-generated advertising is powerful as its  more accessible there by implying that you can get access to it more frequently. This is due too the fact that they can be viewed with various devices. For example, social networking sites such as, Facebook as it also an app which can be used on phones, tablets, desktops... Some of these devices do not require to be plugged anywhere which means you can use it anywhere making it more accessible. In comparison, traditional media  such as TV which are wired so can only be viewed in certain areas such as a house. It is also more accessible as it can be used as shareable content which means you can get access to it more commonly.  Shareable content makes it more powerful as it allows you to give it more exposure and builds awareness. This uses the collective intelligence concept  as if people are spontaneously posting content; "nobody knows everything" so by more people posting it they will feel that due to it having a collective response; its trustworthy so people feel like they are starting to know more.