On a call with a potential client last week:
"We gained 10,000 members in the first month"
That's not a good thing.
10,000 members in the first month is bad. It might be good for a marketing effort or social media campaign, but it's bad for a community.
10,000 members in one month is too many. Most wont ever make a contribution. You can't build relationships and a community culture with that many people joining at one time. You can't convert that many into active members. 10,000 members will prevent you from developing a community culture.
And, don't forget, you only have one opportunity to make a good first impression. You've lost most of that 10,000 members forever.
There are many mindset shifts we need to make when we approach communities, perhaps the most important is to actively resist short-term growth spurts in favour of a long-term growth strategy.