My first public post in G+. 8 July 2011, a week or so after the launch.
https://plus.google.com/+JulianBond23/posts/1qBXL7B367V

I've been searching for something in G+ that let's me see all the posts I've commented on. I can't find it yet.

4 years later. There's still no way of getting a list of all the posts you've commented on.