So far this story seems to trace back to a site called Vatornews.com and an interpretation of tweets on the part of TechCrunch. So it's nothing you want to rush on to the air with just yet but it's a good story to keep an eye on today if it gets confirmed. There have been other rumors about negotiations between the two companies for a while with Google looking to dramatically beef up the offerings in its relatively new Places feature. Groupon has massive customer loyalty, Google has mountains of cash, seems to be a good fit. And if they can get it done and get some integration in place before Christmas, this could be a big deal. But again, just rumors (though persistent ones) for now.
In a related story, you wish you had thought of Groupon.