The search industry was rocked on Tuesday by the news that Alexa had opened its search index to developers, or anyone else willing to pay per-use rates to access and manipulate the Alexa index for whatever purpose. As John Battelle put it, Alexa is "turning the index inside out," enabling all kinds of imaginative vertical engines. Alexa put up a topsy-turvy image-search tool as an example; instead of finding images that match contextual keywords, it finds images according to camera metadata such as brand, model, and image size. At first glance, the service seems revolutionary, taking Google's and Yahoo!'s API generosity to a whole new level and opening the door to more complete search-oriented Web services than a mere Google Maps mashup.

Danny Sullivan attempts to debunk the enthusiasm, though, with a historically informed post that makes Alexa's venture seem like old news, and rather expensive to boot. Danny also points out that Alexa itself actually uses Google to expand its search results; Alexa indexes 4-5 billion Web pages, making it a runt compared to the powerhouse consumer services.

The tale will be told by developers. If they are attracted to the deal, and if news-making products and playgrounds emerge from it, Alexa will have a hit, and perhaps will truly roil the industry. It doesn't necessarily matter whether something is new and groundbreaking; it just have to have the right combination of winning elements.