Maybe it's more accurate to say 'the people who easily fell for Groupon's sales people'. In my area the various daily deal sites have very aggressive sales fleets, who literally go door to door in shopping streets convincing owners to put up a deal. Many of them lose money or barely break even; but then again some of them owe it to themselves (I bought a deal once and went back afterwards; she then said 'I'll give you the same price you paid for the groupon, because other customers have complained that they didn't think it was fair they had to pay more when they came back' Wtf?)
Anyway, I don't have exact data of course, but I've been interested in the business model for years, so I tried to get as much information from business owners as I could every time I bought a deal. The overall picture I got even after a few years (so since 2010-2011 maybe?) was that the typical groupon customer had distilled to the cheapskate vendor-hopping type (before that, when groupon was the hot new thing, it was mostly early adopters who weren't really price sensitive, but for whom getting a 'deal' was more about the social validation aspect of looking like a savvy consumer).
Everybody was suffering and cutting costs. I don't think it was so much as wanting to be price savvy, but rather, wanting to go out and not being able to afford it.
Groupon actually stemmed from a different startup that was supposed to be about something like community building. (The name alludes me, but I used to work for the "parent" company of Groupon and in the same offices as it was getting big. That startup never materialized, but the one they did was got a campaign that if they got x number of people, Motel Bar (which is bar in the same building) would give a deep discount. Andrew Mason, Eric Lefkowsky, Etsy al, quickly realized that that was a real business model, pivoted, and exploded.
Had it been in a different when people were not so price conscious and businesses were not on the edge of going bankrupt, I'm not so sure it would have done as well.
The businesses in that space that seem to still be going strong (see Gilt for example) tend to focus on more luxury items/markets, where they're either selling factory seconds (in the case of retail) or experiences that will likely target a higher class of consumer and will bring them back.
Their concept of the "campaign" became the cornerstone modeling concept for the Groupon platform.
