A. Knowing the conditions in the market is one of the most difficult challenges in business. Even in an existing going business it can be difficult to get a handle on how much volume and revenue your competitors are getting; in a new business the uncertainty is that much greater. One common but expensive tool is focus groups; you ask about an alternative that is much simpler and less expensive, but unfortunately is ethically quite problematic.
The tactic you describe has something in common with "bait and switch." In bait and switch, the merchant attracts the customer's interest with one offer but in the end presents him with a different offer that would probably not have drawn him into the store (or into negotiations) in the first place. This tactic is discussed in Rabbi Aaron Levine's book Case Studies in Jewish Business Ethics. The main problem Rabbi Levine discerns with this tactic is onaat devarim, meaning causing someone unnecessary disappointment or anguish.(1)
One example of onaat devarim mentioned in the Talmud is remarkably similar to your proposal:
If donkey drivers ask you for fodder, don't tell them "Go to so and so, who sells fodder", when you know that he has never sold [it]. (2)
In your case it is even worse, because the people don't merely idly come to you asking for your "product." You have gone out of the way to attract them to your site.
I think that in your case there may be an additional problem as well. Any advertised price effectively makes an offer to sell the product at a particular price. But the tactic you describe goes beyond an offer; it is perilously close to an agreement. Pressing the "order" button constitutes a valid sales contract in current business practice. This could possibly be considered an actual agreement to sell. The sages of the Talmud concluded that reneging on such an agreement, even in the lack of a binding contract, is a sign of bad faith.
It is taught: If there is a [merely] verbal agreement, Rav stated: It is not bad faith [to renege]; Rabbi Yochanan stated: it is bad faith [to renege]. (3)
The rabbis' conclusion is that reneging is an instance of bad faith. So if a person makes a firm agreement to make a sale, it is considered unethical to renege unless there is a significant change of circumstances. (This is similar to what is known today as a "material adverse change".)
Legally your case is not exactly identical. When there is an agreement, even without a sale, the other party will generally rely on the agreement and that is the source of bad faith. In your case the party finds out right away that no sale is imminent so there is not the same level of reliance. But the message may still induce some level of reliance; perhaps the person will try again later, or seek ways to contact the company to carry out the sale.
Market research for a new business is challenging and difficult, but it must be carried out in strict accordance with ethical principles.
SOURCES: (1) Rabbi Aaron Levine, Case Studies in Jewish Business Ethics pg. 55. (2) Babylonian Talmud Bava Metzia 58b. (3) Babylonian Talmud Bava Metzia 49a