Ever since the Internet emerged as a sales channel in the 1990s, it has been thought that one of the chief advantages of e-commerce would be its ability to facilitate the customization of goods and services for consumers. That promise, however, is not yet close to being realized, according to experts at Wharton and Forrester Research, an e-commerce research firm. E-commerce sites continue their struggle to find ways to provide shopping experiences that matter to buyers. Customization is sometimes hard to pull off because of cumbersome manufacturing processes; at other times, shoppers simply do not yearn for products or services tailor-made for them. “When people come up with post mortems about the dot-com crash, they point to bad planning, mismanagement and other big-picture explanations about the way people approach the web,” says marketing professor Peter S. Fader . Some companies have recognized this, but others have not.…