Its true that this system blocks spammers and marketers. At the same time it also prevents a large amount of genuine users who want to take part in the dicussions because its hard to get an invite. So overall the system does more harm than good.
> Invitations are used as a mechanism for spam-control, to slow registrations to a pace we can acculturate and to encourage users to be nice, not to make the Lobsters userbase an elite club.
That works for users who have seen this thread. How does a person who has not seen this thread knows that they have to ask in some random HN thread to get an invite? What about users who don't have an HN account?
On some level it's not open invite and you have to be ok with that.