Investments in brand, and third-party information, provide alternative methods for convincing potential customers that vendors will deliver as promised. This study uses a 13-month panel dataset on 1998–99 Internet shopping behavior and use of information intermediaries by over 30,000 households to examine whether information use undermines brand. Individuals using price comparison sites substantially increase their level of shopping at unbranded retail sites, while they shop less at Amazon. The results have possible implications for both firm strategy and the evolution of market structure. If information weakens the pull of brand, then Internet retailing may grow less concentrated over time.