Much as I wish I could agree with the idea that everyone is a potential customer, I can't. If you target everyone, you are targeting no one. What the web 2.0 era has ushered in, is the ability to target customers more effectively.
The niche is everything. You need to speak to a constituency and meet their needs. Why care? You need to know what bloggers they read, what information sources they like and how and where they receive information. If you think you know that intuitively, forget the Web and open a fortune-telling booth.
I saw a very interesting customer service interaction in a major chain store the other day that I have to share. The woman ahead of me bought many items. The clerk handed her back a small shopping bag with all the items unappealingly squeezed in—almost bursting the bag. When the woman asked for a larger bag, the clerk refused saying, Sorry I can only give you a bag that fits your items with no space or I could lose my job. The woman became annoyed (as I would have) and said, 'If I give you $5 dollars can I have a bigger bag?' At that point everyone in line joined the conversation and a larger bag was finally supplied.
When it was my turn, I asked the clerk why she could lose her job. She said the store was having theft problems and the way she was instructed to deal with it was to make sure that bags had no room to stuff extra mechandise.
Hmm, well that's one way to handle it—punish the customers who buy a lot. Make sure to think through your solutions to service problems, lest they have the opposite effect.