I was a lobster user for 7y. but i find it now way to big, and moderation is strange sometimes. I think, having an additional community is nice. No need to concentrate everybody in one or two website. And there are multiple communities already! I thought I can build one with not such restrictive self-promo rules as on lobster.
The offline community does not have a problem with spammers/impersonators. For online communities this is much more difficult. I don't know what kind of struggle and filtering HN implemented to deal this it. But I do not want to build complicated anti-abuse systems. Right now registration is open, after certain size i will "restrict" registrations.
The https://crow.watch is heavily inspired by lobster. basically same algorithm, same flagging, amd tag filtering. one key difference is [show] tag with dedicated "Show" page. A feature from HN, which lobster does not have. Invite-only where is only to prevent spam in the future. I will rephrase the login page. Will make it "open" and as we see spammers will close down.