A chair, 2 ft tall, black, $5000. There are thousands of sites that hardly provide any information about the products they sell.

Tests have shown that 79% of people don't read, they just skim. However, 16% read everything.

Those 16% are your main target group, the most interested people. If people are not interested in what you are selling, it doesn't matter how long or short your sales copy is. If they are interested, you should give them as much information as possible.

Complete information is the best sales copy. A study by IDC showed that 50% of the uncompleted purchases were due to lack of information. They can always skip parts and click the "buy" button once they have the information they need. But if they read through the whole thing and they're still not convinced, then you have a problem.

This is why you should always strive to say everything that can possibly be said about your product. You cannot be there in person to explain and answer the questions, so your copy needs to do it for you.