The fast-growing deal-a-day business could become a $6 billion market by 2015, said BIA Kelsey. Companies from Facebook to Google to AT&T have joined in with existing players liker Groupon, Living Social and HomeRun, as well as hundreds of local media companies that are also now offering daily deals. Why is the deal business so hot? And what hurdles does it face? Tune into the New Media Minute with Daisy Whitney for answers.