Maybe, it depends.
It depends if you’ve established yourself as an authority beforehand, or you’ve got the respect of those who have.
It depends if you’ve got 5 to 10 community builders to help you out, or a small legion of volunteers.
It depends if you can offer huge prizes for a competition, or reward each and every new member.
It depends if your audience is extremely welcoming to mail-merge, or are predisposed to invite all their friends.
It depends if you’re only interested in numbers, or have a big list of customers who have expressed an interest.
To adapt an old saying, you can build an online community well, fast or cheap. Pick two.