Suggestions for building out a Growth Product Marketing function in a fast growing early stage startup? Since this is not yet a defined role, any suggestions on how to partner with other departments (customer support, product, education)?

Make sure it makes sense first! Do you have a Growth Product team to pair up with? Is Growth well resourced at your company? Is there already a Product Marketing team? A growth marketing team? 

I obviously have lots of questions in order to be helpful here, but I think reading through the other answers here on this AMA might also point you in the right direction. If you answered yes to the questions above, then I would start by making it crystal clear what the Growth PMM team will do, establishing swim lanes, and get lots of feedback from cross-functional stakeholders. 

If you want to follow up with more details, I’m happy to provide thoughts. You can write me at [email protected].

You could probably write a book on this. To keep it simple, start with the function's core purpose or functional anchor. Depending on the rest of the company structure, it will probably be something close to "define how XYZ Company talks about our product(s) to our market to facilitate growth". This examle is Messaging & Positioning heavy. 

From there you should design the function to execute flawlessly against that core purpose. I over-index on process orientation & thinking (blame my engineering background), so I design for inputs and outputs. Generally, this is where functional partnership happens. You'll need information and deliverables from other groups. Likewise, other groups will need your outputs.

With all that in mind, here is where I'd start from a tactical perspective:

1. Have conversations with customers and prospects. This input is less focused on functional partnership, but it would be a disservice to leave it off any list of key inputs for Product Marketers. Find a way to make this happen. It could be win/loss interviews, survey follow-up calls, or joining sales meetings. This is the most important item on this list.
2. Get information from product. Joining sprint demos can be an effective way to see what's changing in your product(s). This is a great starting place becuase it likely already exists as a standing meeting, and they typically ocurr a little before genaral availability of the enhancements.
3. Get customer friction points from Support, Education, Onboarding, etc. These customer-facing teams are a gold mine of information for a Product Marketer. They should be intimately familiar with what upsets customers and what confuses them. You might gather this information from the customer-facing teams along with Product. That will let you collaborate with Product on fixing the root cause of the customer issue.