Imagine you find yourself in the market to buy a new digital camera and, before you part with your money, you want to comparison shop for the best price online. If you do a search for "digital camera" on Google.com, the Web's top search engine, you'll get back over 7 million page results.
Refine your search to a specific model, such as the HP Photosmart 935, and you get back 137,000 page results. Now do a search on BestBuy.com, CircuitCity.com, and Amazon.com and you'll only find it listed one time, and on that site it costs $60 more than I paid for it at Target.
Even though the web makes it easy to search out the products we want to buy, sometimes that mountain of information makes it almost impossible to find the best deal. To solve this problem there are "personal online shoppers" which help you seek, find, and comparison shop multiple offers for just about any product you want to buy, online or offline.
An online personal shopper-type service enables you to log on to a single site, enter the product details you want to search, and then have the website give you back a list of prices and places where you can purchase the item. The personal shopping assistant sites that rate the best don't accept commissions for the sale of items through their services because getting paid based on what the customer buys would eliminate unbiased product comparisons.
The best services make their money by selling targeted advertising to merchants and only displaying products in their search results based on price and features.