Twitter is good for more than just status updates from your friends — the savvy bargain hunter can scope out some killer deals. This holiday season is being dubbed the first "Twitter Christmas," as stores are embracing the social-networking tool to blast exclusive deals to their followers all season long. Some retailers to check out? Best Buy, Toys "R" Us and Gap. Don't want to join Twitter? You can see the deals just by looking at a retailer's feed, no sign-up necessary.