Why do we do this? Why the extra step?
Just like the content on the website and email is curated to ensure the quality of the experience.
The community invitations are also carefully reviewed to ensure proper growth.
The website is open and free for posting without registration to help promote growth and this feature can easily be abused and a target for spammers. Your email and "invitation tree" is a mechanism to help this community prevent spam and keep the site a safe place for everyone.
The only way we can grow is with your invitation of others so please forward your invitation code emails to family and friends.
For an interesting read about invite only communities click here