The Internet has never been a mass market. The new perception of a mass market has evolved because even in the real world the mass market is becoming a thing of the past. The introduction of targeted magazines and cable TV is eroding this a little more every day. Thus people now consider a mass market to be nothing more than a large audience. The Internet is the ultimate network of niche or target markets.
People congregate in areas where their interests lie.
Because of the large amount of data circulating on the Internet, people guard these sanctuaries of interest vigorously. The home page of places like Yahoo and Excite may be the closest thing to mass markets that on the Internet. This is not to say thatall of the pages of these sites are equally mass market. There are less than 20 web pages on the entire Internet where you can guarantee that even a significant minority of the Internet will visit. 20 pages out of a few million is a pretty small percentage.