What does your product management team expect out of your product marketers in product meetings, and how do you measure if your team is delivering this effectively to your product management team?

This depends on the nature of the conversation but in general our Product team expects us to come to the table with an educated, data based POV on how to approach a strategy or a problem.

However, I would reframe the second part of your question. We are not delivering to our Product team, instead together with our Product team we are delivering to our customers.

With this mindset we develop shared KPIs that help our customers find the value in our product -- eg drive X lift in adoption of Y -- and both teams have strategies that ladder up to achieving this goal.

In many cases product marketers are the window to the customer. We’ve walked a mile in the customer’s shoes. We have our fingers on the pulse of their needs, problems and feedback. We meet with customers, sales and partners regularly to understand the market forces at play. We are in the best position to synthesize vast amounts of inputs to help leadership, product management and our partners in engineering to influence product direction.

With that for context, my team is currently measured on the following metrics (for a cloud service that identifies issues before they occur using advanced proactive intelligence). 

1. # of customers/companies registered 
2. # of active users 
3. # of features used 
4. # of issues proactively remediated
5. # of qualified leads

It depends what the meeting is. More generally what PM expects from PMMs include:

1. Intelligence on Customers - Trends, NPS data, insights from conversations or a Customer Advisory Board. In other words, what are you hearing from customers or trends in data are you seeing that should or will impact product or the strategy. 
2. Intelligence on Competitors - It's important to be aware of what competitors are doing, but not blindly follow them. With that said, what products are they releasing and how is your differentiation changing.
3. Intelligence on the Market - For example, Apple recently announced "Mail Privacy Protection" as a part of their upcoming iOS15 release, which impacts a wide range of marketing technology companies. Learning about this, and working hand-in-hand with your Product team to come up with a Point of View on these market changes is good for your organization, and great for Sales/CS as well.

There's a whole lot more than these 3 as well such as pricing and packaging, GTM strategy, analyst relations, and more - but the broader point is that if you can collect and synthesize this information for product it's a huge value add.

To bring the voice of the customer (and all of the external market concerns top of mind to a customer) to help the PM team build the best product possible. 

Feedback in review cycles or direct questions in 1:1s between leads helps. But its also valuable to read the room when you sit in on meetings with your team. Are the PMs engaged? Is there a buzz in the air or does it feel flat? While a PMM is talking/presenting, are others multi-tasking or are they participating? If your PMM team is bringing value to your PM team, then your PMs will act as though they value the meeting vs acting as though the meeting is a thing they have to do. I use that as a pulse check to see if PMMs are delivering impact effectively to stakeholders. 

What our PM’s expect from PMM is to represent the voice of the customer. This might take the form of articulating customer sentiment about a new-product idea, feedback about an existing product, or overarching customer needs around a larger “job to be done” like building their brand or generating quality leads for their business.

Our team delivers a “market insight report” to PM roughly once per half that is designed to shape major funding decisions on a 12-month horizon or longer; usually, this report incorporates insights collected during customer councils or major industry news and in-house market research. But week to week our PMM’s sit in with their product counterparts and deliver recommendations about specific feature ideas or product capabilities for something that’s being built and tested right now. The PMM in this case usually derives their insights from recent beta-customer feedback gathered via survey or calls, sales rep feedback about a new product we hear through our official sales tiger teams, etc