CheapTweet and CouponTweet are mentioned in a SmartMoney article on companies utilizing social media to offer price incentives to customers–a very prudent use of the platform, in my opinion.
I think we’ll see many more Twitter aggregators like the two above. It’s simply too hard to find things in the stream. The incoming Tweets come in at a random and rapid pace. So, businesses are being born to meet that challenge. Good stuff.