Cc

Limit the number of people involved only to those who would benefit from participating in the conversation. 

It's not rude to exclude somebody who were previously in Cc, if the person does not need to be in the loop any longer.

We're all busy. Let's cut the noise.

Use email for discussing short issues that do not require fast reaction by a small number of people.  

If your topic involves the whole team (and you're 100% sure) write to the Google group or space.

For a coding matter, consider having an issue or a pull request instead, and share it with the intended audience.