A couple of years ago Groupon was the in-thing when it came to daily deals. Now Groupon says we're less likely to open those emails and even less likely to actually act on them. What happened?

Marketing expert Sucharita Mulpuru says she thinks Groupon will remain the daily deals leader, but it's probably maxed out.

"This is a great, profitable business model it's just not billions and billions of dollars like the Street thought it was."

Groupon reported losses wider than expected recently.

"It's a great business that's limited in size and it will be the dominant player in this daily deals space. But it is what it is at this point and it's probably not going to be significantly larger."

Not every retailer benefits from Groupon. Houston massage therapist Dick Juby says he didn't get as much money from offering a Groupon deal as he'd hoped.

"It hasn't hurt my business, but it did not help my business either."

Juby says one bad review from a Groupon user can do a lot of unwarranted damage, too.