I had planned to attend, but NIPS "sold out" within a couple weeks before I could make arrangements. NIPS growth has been absolutely tremendous. Being unable to register made it impossible for my lab to submit workshop papers. One of my students got a travel award to attend a Women in Machine Learning Workshop, but only the tutorial day was open for booking.
Unfortunately, it doesn't seem like next year's venue in Montreal is any bigger based on the statistics I looked up.
If you want to ask questions/add comments to the papers being presented, the Fermat's Library team set up a page for that http://fermatslibrary.com/nips
This comment seems to have been downvoted and then flagged, but a reminder that TITS (Transformationally Intelligent Technologies Symposium) is a real, if humorous, sister conference of NIPS: http://www.tits.ai
Deepmind: https://deepmind.com/blog/deepmind-papers-nips-2017/