How do you know where the line is when it comes to learning about the product vs. trusting your product business partner to keep you informed and educated on the most important factors?

To be an effective product marketer my view is that you need to be a deep expert on your product. You don't need the same technical expertise as your product management counterpart but you need to deeply understand the customer, their pain points, and how your product solves these pain points. AppFolio is a B2B SaaS platform that property management companies run their entire business on - accounting, maintenance, marketing, leasing, rent payments, everything is done through our platform. It is a complex product to understand and the steep learning curve is compounded by our team members neve being users of our product themselves. My expectation is for everyone on my team to be able to demo the entire product at a high level and to be able to give a detailed demo of the area of functionality they own. 

However, my expectation for the team to gain deep product expertise in their role is unrelated to their relationship with the product management team. It is essential that PM and PMM have a relationship of profound trust but that trust should never be an excuse to not learn the product in full. Without deep product knowledge, product marketing will not get a seat at the product strategy table and instead be relegated to just doing launches and go-to-market enablement.

As a PMM, it's crucial to be the expert in the market, including the user needs & competitive landscape, while you can lean on your PM partner to be the expert in the technical details of the product you're building.

With this in mind, I would draw the line based on the type of question you're answering. If it's about the user's needs or competition, then it's your job to educate the PM/rest of the org.

If it's about the technical details of how the product is built, then it's okay to lean on your PM/Eng counterparts to get up to speed.

That being said, the ultimate goal is to 'mind-meld', so that the PMM team gains a deep technical understanding of the product, and the PM team gains a deep understanding of the market/user needs. This is when the magic happens!