Clegg Ivey, a vice president with VoIP company Voxeo, recently told me a story about a restaurant near the company's Orlando headquarters that was losing track of what made it successful.

The restaurant's food wasn't something you would go out of your way for, except for a goat cheese appetizer that Ivey said "was to die for." The restaurant became a favorite of the Voxeo staff almost entirely because of the appetizer. But the staff recently learned that the menu had changed and the goat cheese appetizer was no longer on it.

The restaurant had hired a new chef who wanted the menu to reflect his vision, not the past chef's. Ivey told the story to point out that it is easy for companies to ignore what products or features attracted the customers they already have. Ignoring this risks alienating those customers such that they may quickly become ex-customers, just as most of the Voxeo staff has. Ivey offers "don't take goat cheese off the menu" as a phrase that can be used to remind companies not to forget what the customers liked about the company.

The reverse is true as well - don't forget to replace what the customers hate. Preserving bad products because you know how to make them is at least as much of a risk as tossing out the good ones.

The goat cheese admonition must not get in the way of new products or product evolution - maybe the new chef at Ivey's restaurant has some very good recipes that will eclipse the goat cheese appetizer.

But it will be harder to get the folks from Voxeo to try the new menu because the lack of the specific dish they came for means they are not going to the restaurant. Maybe for that restaurant it would have been better to phase in the new, eliminating the good dishes from the old menu over time.

Obviously, the dilemma of how to evolve products is not limited to the restaurant business. Apple made significant changes to the user experience when it moved to OSX from OS9. Not everyone was happy with the changes - I have friends who have never made the switch because they did not like the new look and feel. But overall, many more people like the OSX environment than were upset about the change.

Some early reports about Microsoft's Longhorn (now Vista) complained a great deal about the changed user experience, predicting significant increases in user support costs. I have not seen a lot of these reports of late, but I do expect many corporate Windows users will soon be wistful over today's Windows (but not as many as Microsoft wants because the incentives to change to Vista will not overcome the desire for the familiar in many users).