Currently in a five city trial (Atlanta, Austin, Dallas, San Diego and San Francisco), Facebook deals focus on users first purchasing vouchers using money or Facebook Credits, the vouchers later being redeemed online. users can Like deals without or before buying them as well as invite friends and share deals through their feed.

Bloomspot functions around the classic "come and get it!" model wherein users create an account, sign up for a deal they like (i.e., high-end sushi, some time at a spa or a trial session at a local yoga outfit) and have a given amount of time to act on the deal (as represented by a countdown timer on the web site).

At the Voice Deal of the Day, users log in, create an account, choose from an available city, select the deal of the day and buy into it. The site offers a full profile as to the vendor offering the deal, the fine print and additional images of the product in question (in this case, a gallery of cupcakes and desserts from a pastry shop in New York).

At LivingSocial, the package is email centered, users receiving updates presenting offers within a city for the day. Once a deal has been purchased, you get an email redemption voucher for the following business day. Users can also hop on to the Instant Deals section of the site to snag deals starting within the next 15 hours or less, the site turning a profit from its offer fee.

Let's face it: Google's not going to step away from the deals market, even if you ask them nicely and offer them a really tasty dessert not to do it.

Google Offers is currently under construction and active in several text markets, the site functioning around a "deal-of-the-day" style in which various deals are e-mailed to you each day and prepaid offers and vouchers are then purchased by the user.

If you're across the pond in the United Kingdom, you might like this. Or you can wait for it to expand to the States and get in on it a bit later.

Crowdity taps into the economies of scale idea, presenting a daily offer on its web site wherein a given number of users need to purchase the offer for everyone to get the savings. If the minimum is met, everyone saves. If the minimum isn't met, the deal falls short and no one saves.

Like similar sites, BuyWithMe offers a daily deal in each of its markets, the deal becoming available if enough users purchase the offer. Recruit three friends into the offer and your offer fee is waived, the site also offering a $10 reward incentive for attracting additional users.

Similar to the other deal sites, Plum District simply has you sign up, see what the daily deal in your city is, purchase it and you'll receive an e-mail confirmation/Plum Certificate that can be taken to the vendor for a discount on the item in question. The site also offers incentives of $5 in Plum Dollars per friend referred, complete with Facebook, Twitter and e-mail based social networking tools.