Going to https://instapaper.com just displays a blank page with Safari 10.0. Seems a bug introduced with MacOS Sierra.
Checking on Twitter suggests there is a bug with "View Controller" in Safari. I have submitted a bug report to Apple but not sure how long it will take (if ever) to review.
I use the "Send to Kindle" feature mostly which only works on the free accounts via their website "Settings" page... or automatically at night in my case. Annoying but will survive I suppose.
iMac (Retina 5K, 27-inch, Late 2015), macOS Sierra (10.12)
