Around 18% of the people responded to the poll said they are hosting on a PasS, which I assume is mostly on Heroku.

https://news.ycombinator.com/item?id=3466168

I did not respond but I use GAE. I think I felt better when I knew the number was just made up.

I was going by other private surveys of specific subsets of the hn population. Number of companies, it's 10-20%. Lots of smaller companies or earlier stage; basically everyone who does Rails deployments (since that was originally Heroku's strength).

GAE is the one very few people are using or want to continue using, especially after the Google price hike.

I still prefer colo/managed hosting at scale, with EC2 for trials or surge capacity, myself.