If you wanted to be reductive: if the domain ends in .com, you can assume the submission is an ad. Some ads are better quality and worth discussing and some aren't.

Nothing nefarious about it -- it's just a deliberate strategy on the part of companies like Retool or Supabase or Fly or whatever to market their services to this target market.

I have no idea how many actual sales conversations it leads to, but it sure is effective at convincing many HN readers that those are cool companies selling cool things...