Scaling with customer scale

Why is this change being made?

In the past couple of months, we've had a number of interactions where a question was raised of what should be built in the Rails monolith, and what needs to be considered outside of the monolith. This is not a first time we have had this discussion in Engineering, and the discussion usually takes us towards velocity vs. scalability discussion.

In a discussion with @joergheilig, we agreed to raise visibility of this fact and to start a conversation around how we make early stage decisions when building functionality that can impact our customers and us, and define how to equip everyone to be able to make this decision when it matter.

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