I understand that you want the startup to interact with the comments and I also understand you don't want them to miss an opportunity of receiving and answering

I understand that you want the startup to interact with the comments and I also understand you don't want them to miss an opportunity of receiving and answering feedback, but I'm wondering if it would make more sense to have these automated messages come from a Product Hunt twitter account that's not associated to a person. I believe this would solidify that it's an automated message. I get the feeling that you're trying to play the messages off as not being automated as they come from Erik, but people already know they're automated. The gig is up. You could simply create an account such as "ProductHuntNotifier" or equivalent and remove any ambiguity. I still think that the messages are both relevant and important. You're in a unique position where you can even manually add and promote new startups to Product Hunt yourselves followed by automating a tweet out to the founder(s) and growth hack user acquisition that way. This seems to be the approach you're taking. I do applaud the fact you go so far as to do the legwork of finding the twitter accounts associated with the startup; that task is by no means automated. Most people can't take this approach as they have nothing beneficial to offer the user they're tweeting to. Because there's some value add to what they're doing, I'm not sure I'd say it's a cut and dry case of calling it spam given it's not fully automated and the startups in question are getting promoted. It seems mutually beneficial in many ways.