What are some of the *worst* KPIs for Product Marketers to commit to achieving?

Well, to quote Rush, "if you choose not to decide, you still have made a choice." I would say the worst thing you can do is not commit to something. Pick one and roll with it - you can always adjust if it doesn't fit the business. Owning a number is the best way to establish leadership and priorities.

The worst are metrics that don't directly lead to revenue. "Site traffic, asset downloads, content creation, the PMM seeks not these things." Find the outputs that align with your key GTM partners in the company, and drive those.

Great question. A couple come to mind that I would advise against signing up for:

• Sales-enabled revenue. There are so many variables and phases here -- from demand generation, to the sales team actually following up with leads, to the leads actually showing up for a demo, to the sales team effectively selling them -- that it's too big and far removed to commit to. Better to pick some metrics within this (like MQLs, or opportunity to closed won rate) that you have a better chance of influencing with specific tactics. 
• NPS, LTV, net retention or churn: Similar to the above, there is way too much that goes into these metrics that PMM has little control over. If you want to tackle this, design it intentionally (e.g. customers who do this maturity model pilot with their CSM should have a higher LTV after 6 months than those who don't go through it). 

Awesome question - I think there are two buckets that make up the "worst" KPIs for PMMs to commit to achieving: KPIs that simply track task completion and KPIs on which PMMs have no direct impact. 

KPIs that track task completion are so tempting because they're straight-forward and, thus, we've all taken them. A binary "complete/not complete" for stuff like messaging briefs, First Call Decks (FCDs), analyst presentations and RFP response docs is important to track, but they're not KPIs. If you can show if/when/how they're working and contributing to revenue, product adoption, etc. you're golden.  If not, there'll be an incentive to create more and more of this kind of content that nobody knows abour or uses until, over time, other teams start to question how PMM is helping the business vs cracking out stuff that just gathers digital dust.

Also be wary of important GTM KPIs (like ARR, MCP, net renewals) over which PMM has no clear, direct impact. MPC, for example, is dependant upon strong messaging and positioning (which is PMM bread and butter), but unless PMM has a say in audience targeting, channel investments and other demand/growth factors, try to isolate signals that show how the messaging is effective for pipeline generation.  PMM can't simply be a "ridealong" on these types of metrics and still maintain a strategic charter of their own.

This is a great question. As mentioned earlier, there are so many shared metrics between PMM and other parts of the business - ie Marketing, Product, Sales. So when committing to a specific KPI, make sure you and your team truly are able to influence it.

Therefore don't tie yourself or commit to anything you are not able to map back to how you influence that. For example, website or landing page traffic. Sure your messaging may have helped attract those visitors but it will be too hard to attribute this to your work alone.

In a similar vain, there are a lot of instances of PMM teams reporting on how many products or features they launched. The launch is just the tip of the ice berg. If you're launching dozens of features a month but no one is using them or finding value - this isn't success. Make sure to double click on these kinds of vanity metrics to connect the KPI to business value