I have a domain name which will eventually sell 10,000 products in different categories. However, to start off with I am only selling one category of products. Then later on as we generate cash for more stock I will add more categories. So my question is this: do I use this domain name (that I will eventually sell 10,000 products on) or set up another domain name for this one category only. Will I be harming the main domain name because it only gets known to sell one type of product.