We're launching a new experiment to help users avoid the spam label.

Should help people who are good faith trying to engage and adjust how they cast.

Reminder, if you're casting in your own home feed, channel or replying to people you who follow you, the spam model doesn't focus on that. 

It's only if you're excessively replying  to people who don't follow you (with no engagement).

does this not affect new users? most people won’t follow them at first, and they have to reply people to make friends/connections.

There's a big difference between a few replies without engagement and dozens or hundreds.

true.

what does this mean for users already labeled as spam? 

it gets permanent or the label will get removed and they get another chance with the new system.