None of these things are exclusive to Groupon, though. There are already lots of aggregators for coupons where you can check if you can get something cheaper.
The point is that these aggregators are not in everyone's mind today. Groupon can use their current offering to reach everyone's mind, and then use that positioning (and therefore you going to their site) to do price comparison, focus on the user choosing specific topics of interest, etc.
Yes but the counterpoint is that it's an easy-to-replicate idea
Having a large mindshare in a specific niche is neither an idea nor is it easy to replicate.
Yeah but my point is, the only point of Groupon is their web site. So I don't see the point of them throwing sales people at small businesses. They need mindshare with their website, and I don't think you can drive internet traffic with sales people.