When you click on one of the categories on the Etsy home page (ie, jewelry, childrens, books and zines, etc.), at the top of the page is a sponsored section of about 20 items. This is the showcase. I typically get about 100% more views when I purchase a showcase, and I've gotten a few sales from them as well. They cost $7, so I usually only do one every month or so. They work better than the ads, I think. Once you purchase a showcase, you can line up the item/items you want to place in the slot.