I don't think @MastodonEngineering 's proposal of suggesting community run servers at signup is going to work.
Bear with me:
The difference between funneling new users to the foundation-run instance unless the user makes an active choice (personal invite from existing user, selecting from themselves making an informed choice etc) is that two different people both joining "Mastodon" will be subject to completely different community and moderation standards. Sure, we'll require some sort of minimal agreement, but that still leaves lots of room for ... let's say, somewhat power-hungry BOFHs.
It's a well known fact that there are a bunch of people running instances on Mastodon who believe it's their job to "sort out" what's suitable for their users to see or not see. A bit authoritarian, if you wish. Others think it's their job to enable their users to make their own choices, unless there's actual content that violate server rules.
There are servers on joinmastodon today where the admins, completely by themselves, decide to instance block users from other instances that they don't like - without them having broken any server rules whatsoever. Their "own" users on those instances have no say, and no idea why other users on Mastodon never respond to any follow requests.
If you take a step back and look at this from the perspective of random user Z just wanting to "get Mastodon" and sign up for what seems to be a local "Mastodon server" it doesn't matter how many disclaimers we put up - when this happens they're going to get pissed off anyway. And rightfully so.
I think it's better to continue to funnel everyone through the foundation server - and extend the instance move support to move over posts. That way everyone can make informed decisions they can at least understand the effects of.
