It just might be corporate image, it might be information, it might be software, or it might be toasters. The best thing to sell on the Web is information. It is easy to provide to your users. You do not have to do anything more to provide it to 1,000,000 users than to 1 user. In one way, we are selling on this website our experience with the Web, and how to do business here.
Software is also good to sell on the Internet.
You can provide a trialware version which can be turned into the full version after the customer pays. You really have to put a a good case for a person to buy off the net. You must provide exceptional benefits, ie you are much cheaper. Since you do not have the overheads of a shopfront, you should be able to do this. There is no way a physical shop can do this.