The websites offer a variety of designer (both big name and up-and-coming) clothing, shoes and accessories. A couple of them offer men's and children's clothing, and some, like Rue La La and Hautelook, even offer perfume, makeup (like Stila!) and home decor sales.
Items are usually offered at better than 50% off. I'm currently stalking ideeli for a particular pair of 85% off heels to pop up in my size. Another nice aspect is these are not super-model sizes. There's usually a broad range, instead of just 0's and 2's. These are good sites for scoring deals on those investment items.
Want a tiny taste of what's available today? How about the fabulous wrap dress below from Gomatta Girls for $45 instead of $395?!? Also comes in black, white, and a pale blue floral.