Chris Dixon recently wrote (in an incredibly brief post) that recommendation systems are features, not products, and pointed out that Hunch was only compelling after being bought by eBay, where it successfully powers both recommendations and discovery on the site (not 100% sure on this). I agree with Chris and have a few notes.
1) Recommendation takes initial desire and channels it: you want a TV but you’re not sure what is the right kind, it tells you the right kind and thus makes it easier (lowered inhibiting pressure). Discovery creates desire (higher promoting pressure): you weren’t thinking about food, but you are now. People tend to mix the two up.
2) The reason that recommendations don’t stand on their own is because the intended action is to satisfy a desire. If you are looking to buy a TV, the end state is the purchase and telling you which one to get doesn’t end the needstate. So you’ll get outcompeted by anyone that does (like Amazon). The only place where you can have just a recommendation engine is where you can’t complete the needstate in that medium: I can recommend recipes, for example, because there is nothing more than can be done online. But these are dangerous plays, because you can get outcompeted by anyone who brings it closer to closing the needstate. Recommendations worked until Amazon made it so you could get recommended and complete the transaction in one place (just ask CNET).
3) Discovery, in contrast, can work on its own. Not just because of SEO (Chris’ explanation), but because true discovery isn’t the same as a recommendation: it actually creates desire, often from adjacent desires. Take Pandora. Nobody puts on Pandora to purchase new music – that isn’t the point. But in the course of satisfying one desire (good background music), it occasionally creates another (the urge to buy a song). If you are browsing blogs about fashion for entertainment, sometimes you find things that you then want independently of your previous desire: buying something doesn’t make you want to stop reading fashion blogs for entertainment That is generally a clue that discovery happened, when you do something but it doesn’t diminish the need that you came for in the first place.
Bonus: discovery and recommendation map to the two ways I break advertising down for people often as well. Some ads are about creating a desire for a thing you didn’t previously want, often by coupling them with other things you want (like selling beer with naked women). You didn’t want a beer, you did want a naked woman, now you do go get a beer, though it doesn’t quench your thirst for a naked woman (studies suggest it may even enhance it). Other ads, in contrast, are about taking existing desires and channeling them. You were already thinking about buying a car, you should buy our car, because it is the best car. It fits your need. Buy it and you will no longer need to buy a car.