
Out of interest, and in my spare time, there are a number of sites and resources I keep a pulse on:
NPS Benchmarks
With Net Promotor Score being one of many metrics Customer Success uses to gauge overall satisfaction with customers, this site lends current data on industry NPS scores ... eBooks on NPS ... as well as case studies, white papers, webinars, and much more on all things NPS.
The Customer Success Summit
Totango, a customer success SaaS solution, hosts an annual Customer Success Summit where thought leaders in the space, and practitioners, come together to learn and collaborate towards the greater cause for fanatical customer success. Executives and customer success leaders from major software companies support and/or participate in this summit. I highly recommend attending. But, if it isn't possible to attend, which has happened to me a few times, the content is recorded and shared so you can get the latest on what's going on in the customer success industry!
Customer Success University
Gainsight, also a customer success SaaS solution, has what they call Customer Success University. They have a catalog of customer success online courses that are a good resource for novice-to-seasoned customer support professionals. I've recommended many of these courses to my own team for professional development, and they are also a great way for professionals considering a transition into a customer success organization to gain insight (pun intended!) on what to expect!