This is a good question and I can see why you ask asking it. However, just because a company is Internet based and worldwide, it does not negate the importance of a target market. Here are some very important considerations.
First, not all people trust the Internet. So, your first target group are people who trust the Internet and would not mind buying products online. This will mean that your target group is probably younger and have some experience with online shopping. So, your products should probably engage this demographic.
Second, even if people trust online vendors, many people will not want to ship internationally. There are so many scams out there that it is frightening to may to buy a product from an international online vendor. This is an important consideration as well.
Third, you need to ask who buys online anyway? Most likely people who have busy lives are more apt to purchase online. If this is the case, you might want to offer products that busy people may need.
In short, by reasoning things out step by step, you will be able to come to a good target group. Some insights from marketing will help.