I think you need a 5th takeaway: write a follow-up blog post about how your HN post got you 1000 users, subsequently getting you another 1000 users that missed the post the day before.
how about a 6th takeaway in a follow up, in which he discusses retention of these initial 1000 users? I think it's great he was able to obtain those numbers early but I think those users are a bit ephemeral.