I applied on Groupon via their website and heard back rather quickly (2-3 days) from the hiring manager who set up one of her recruiters to speak with me for 30 minute on the phone. After successfully completing that stage, I had to wait a little over a week for the next stage which consisted of 4 Skype Interviews ranging from 45 minutes to an hour. The first interview was with two peers. The second interview was with a VP of Engineering. The third interview was with the hiring manager. The fourth interview was with the director of the group (the hiring manager's manager). I felt all interviews went well but some of them such as the peer interview, and the director interview had gone phenomenally well. After those interviews, I was told I'd hear back regarding results within 2 weeks.
Towards the end of the 2 weeks, I received an offer from another company and let my interview team know. They promised a quick turn around and they delivered. I received a call from the hiring manager the following business day to alert me that they unfortunately were going with another candidate. Upon digging to find out where I missed the mark, the manager was very nice and let me know that the decision came down purely to location. I was a relocation candidate that would require a bit more ramp up time for the area than their local candidate who could hit the ground running. I thought it was very commendable that they would not only call me instead of emailing, but also letting me know why I was not chosen.
I think overall this process was an excellent one and would look forward to possibly working for Groupon in the future sometime.