Follow the link to read Gundotra’s blog post about leaving.
Here’s what Larry Page posted in the comments:
Vic — thank you for a tremendous almost eight years at Google. You cut your teeth on our mobile apps and developer relations, turning our disparate efforts into something great. When I first used turn-by-turn navigation, it blew me away. And, walking onto the stage at I/O last year, it was amazing to see developers so excited about Google. These were vintage Vic projects. Then you built Google+ from nothing. There are few people with the courage and ability to start something like that and I am very grateful for all your hard work and passion. I really enjoy using Google+ on a daily basis, especially the auto awesome movies which I really love sharing with my family and friends. Good luck with your next project after Google. In the meantime we’ll continue working hard to build great new experiences for the ever increasing number of Google+ fans.