Imagine a world of search in which every item that's posted to the Web is immediately scanned and dispatched to people who have expressed an interest in it. This is new arena of search that companies such as PubSub and Technorati are creating. PubSub founder Bob Wyman calls it prospective search, and he predicts it will destablize many entrenched businesses. An example: Monster.com. If you tell PubSub that you're looking for a Wharton MBA who's fluent in Mandarin, and such a person posts those details on his or her blog, the search engine makes the match for you--with little need for a job-site intermediary.
Wyman foresees a world in which prospective search engines bring buyers and sellers together. In addition to Monster, this could also challenge eBay. In this free-range world he describes, the extra services that sites offer, from transactions to trustworthiness rankings, become ever more vital.