Having historical pricing data seems particularly interesting. I've thought about building a fashion site that predicts pricing trends so you can predict when to buy items on sale, and it seems like this could serve as the pricing infrastructure.
I wonder how I can tell what product sources are available, and whether new ones appear? I.e. is this only going to cover amazon.com, or does it know about nordstrom.com too?
That's a great idea. Pricing trends analysis could be done through the historical data we provide across the different merchants.
We do provide the affiliate purchase links to the products, available under the 'offers' field. Currently you can only figure out when new merchants appear by polling the product ('pull' mechanism). One idea which we have been toying around has been a 'push' mechanism where you can subscribe to a particular product through our API and we would notify if there has been any change (price change or new merchant selling it or product has been discontinued). Drop me a mail at varun <at> semantics3.com if you want more details or wish to bounce off ideas.
I wonder how I can tell what product sources are available, and whether new ones appear? I.e. is this only going to cover amazon.com, or does it know about nordstrom.com too?