"Customer success" has been creeping into biztalk lately. According to Ed Zitron it refers to that subspecies of salescritter that works with SaaS ~~victims~~customers to ensure they keep expanding their buying.

The industry called it “field engineering” previously, and “customer support” prior to that; renames happened every time the execs heard how this portion of their business is only a cost center and can easily be done by chat bots (to which the customer success people would say, good luck with that).

It's like how "marketing" became "UX research/design"

It's just support and upsell

Usually it's the part of the org that is directly interacting with big, corporate customers. Those customers can and often do directly shape how a product works. It's like a sales team, but focused on existing customers with big contracts (that might be expanded), rather than acquiring new customers.

But admittedly, this has just been my experience. I'm sure it's probably not universally true.

in a startup model where product directly implements function requests from clients, it'd be the head of deciding which functions, sprints, priorities etc.

And/or ensuring that clients are handled well enough so they're not at risk of churn at the q3/q4 turnaround.