Most stores you see online have a wishlist feature, but they are all siloed into their own service. WantWorthy gives you one wishlist for everything you could want on the web.
The service uses a photo-oriented approach that's very similar to Pinterest. However, it's aimed specifically at things you want to buy so the prices, store and brand are all prominently featured. Amazon Collection also offers similar functionality, but as one might expect, it's limited to Amazon products.