Found a 4th one which is more important than the others (updated the blog post): it also looks like launchrock only checks whether an email is well formed but

Found a 4th one which is more important than the others (updated the blog post): it also looks like launchrock only checks whether an email is well formed but not whether it exists for real or not hence people can leave fake, misspelt or, worse, other people’s addresses. This would be easily sorted by a double opt-in.