That`s a great idea, I love it! Advertising as content, you just can`t beat that.
I think a good traffic driver would be to have a nice, beefy review of each of the few products you post every day.
I also think it will be a tough site to get up and running unless you start off targeting a pretty tight niche. For example you could target automotive aftermarket stuff to start with, then later add other niche markets as subdomains: e.g., homegarden.sweetdealoftheday.com / organic.sweetdealoftheday.com / beauty.sweetdealoftheday.com / etc.
Or, you could do it geographically by city: portland.sweetdealoftheday.com / sf.sweetdealoftheday.com / chicago.sweetdealoftheday.com. If you did it like this, I could see opportunities for selling the business in a couple years to Citysearch or Local.com or one of those locally-focused search type sites.
Another thing you could do is have a "sweet deal of the day" daily email in addition to the website, not duplicating the content but just highlighting it as a way to drive additional traffic. The beauty of this is that building up a fat database of consumer email addresses & demographic info is a relatively inexpensive way to add potentially a great deal of value to the company. The database itself will be worth money, and you can partner with other companies to sell permission-based access to subscribers who elect to be included in partner notifications.
I think this idea has a lot of legs. I think if you plan & execute it even half decently you stand a good chance of being successful, especially in a cooling economy where everyone`s looking for a sweet deal every day. And so much the better if you decide to sell it and bank a few million$!
Very smart idea, love it. I hope you will keep us posted if you decide to go for it.