In my opinion the most important part of internet marketing is to define your target audience. Then use as much sources as you can to reach it! I'm prefer to start with social media, such as fb, twitter, and instagram.
Yes, this is a very powerful tool. Many people create target groups in social networks. And if you offer there sa product, then undoubtedly you will find many partners. But with each partner you need to have a personal conversation and explain why he should buy your product
It is very powerful indeed, you need to find your target or niche target. Because these people are your potential buyers. Finding niche target is not that hard specially with the tools that the social media are offering. You just have to be unique and catch the eyes of your target audience and make a sell.