What are some KPIs that you find over-hyped and/or unimportant?

I must ask back: in what context? Because PMM can flex its priorities and alignment towards Product vs. Sales vs. Customer Success (or even Marketing demand gen/comms, I go back do ensuring that whatever KPI is set supports a top 3 corporate objective that the C-Suite cares about.

If you forced me to point to a specific KPI, I'd pick #leads or $pipeline generated. You see this especially at smaller, early stage companies where the Marketing team is just getting built out and the team is trying to distill down to 1 KPI a few team members can get behind -- you can map the success of a new product launch... or the ability to feed sales... to top-of-funnel interest. 

However, I'd work backwards and instead set the KPIs to the ultimate objective vs. something in the interim. E.g., If you set the KPI as X% activation or adoption you would need signups (leads) to get there anyway. If you set the KPI as X$ revenue you would need pipe to get there anyway, etc. And this isn't a knock on the demandgen or customer marketing teams. Leads and pipe are important metrics, just not for PMM.

My runner-up unimportant KPIs for PMM: # views of a particular piece of asset, followed by aggregate NPS (unless you have a very mature and built out team that can consistently cover all personas and a ton of ground).

Any KPI, no matter how small, can be important if it’s tied to organizational performance. That said, my biggest pet peeve is when PMMs attempt to show the value of their team with KPIs that aren’t actually tied to anything outcome-based. 

A common one that comes to mind is setting goals for “views” of a specific piece of content. Content views are something that should be tracked for diagnostic reasons, but not as a team KPI, unless you want to become a team of “list marketers” checking the box on activities that you just do to hit your marks. 

In my view, it’s way better to assess how your team’s content meaningfully contributes to speeding sales cycles, or converting a trial customer to a paid user. If you can make those kinds of outcomes the metric, with the content simply being a supporting tactic, you are in a much better place to be strategic within the company.

First, I think any KPI that's connected to organizational goals no matter how small or large is important. There's so much value in aligning cross-functionally and pursuing goals that differentiate and move your company forward and aren't just department or function-specific.

That said, I personally find some view-based metrics to not be helpful. They can help directionally but ultimately aren't reliable as sole KPIs for many initiatives.