Ah, the splendor of online shopping ... endless pages of items in every shape, form and color imaginable, discount prices, free shipping offers, a few clicks of your mouse and voila your latest purchase is at your door begging to be opened.

Online shopping is an alluring world and now a host of new sites are taking that allure one step further with members-only shopping sites. These sites – such as Rue La La, Ideeli and Gilt – are taking the online shopping world by storm, offering exclusive designer discounts and private sales to a privileged invite-only membership base.

Hautelook is free to join and doesn't require an invite, but offers a "friends don't let friends pay retail" incentive by giving you a $10 credit each time one of your friends makes a first purchase. But what really happens behind the velvet ropes of these exclusive shopping sites? Often times it's not as glamorous as it sounds.

Those who are "on the list" receive e-mail notifications with countdowns to the hottest upcoming designer sales, creating a frenzy among shoppers to be first in line. These virally-marketed private sales last anywhere from 48 to 72 hours, but the stock is very limited and if you don't act at warp speed, it's nearly impossible to find what you want in the size you need.

So amidst the fast-paced excitement, the ticking clock, knowing someone else might get something before you, you make an impulse buy thinking you can just return it later. Well think again: many of these sites have tricky return policies and some have no return policy at all.

And what's more? While these sites are able to strike some exclusive deals with select merchandisers, there are just as many offers on these sites that aren't really that exclusive at all. Do a quick Google search and some items can even be found for less.

There's no doubt that these members-only sites create a fun and thrilling new way to shop. They have their perks, but be aware of the risks. It doesn't always pay to be on list.