Humble suggestion: Have a separate page on the site that shows stories which have had strong negative penalties applied to them, whether from being flagged or moderators.

Suggestion: Make anonymized graph data available on submissions and flaggers so we can spot flag/upvote cartels. This would make for a great final project for some college course.

I suspect that the software does that automatically on the server. Given that 'cartels' are likely to be automated and hence at web rather than human scale, at least some of the counter measures probably should be as well.

Well those are the flagrant cartels. I hear there are pure-human cartels too. I see emails and Facebook posts and en-masse emails asking for Product Hunt up-votes from time to time from some VC associates. I imagine there is a similar thing going on on HN (but what do I know...i'm just a tiny startup staring at PyCharm most of the day.)

Because it is mostly a site for press release type content, I suspect Product Hunt has less incentive to discourage those sorts of get out the vote activities versus Hacker News. And Hacker News users have more incentive to flag posts that rise for reasons other than interesting content or comments. I mean, if I have an informed expectation of what I will get on the Product Hunt front page and it is different than my expectation about the HN front page in part due to the way get out the vote activities are treated.

Just change it to be less effective as it becomes more popular.

There's no reason to have a 'flag' link once a story hits the main page, for example.

Or just monitor the stories that get flagged off the front page (~25 over several weeks according to the post) and take appropriate measures (e.g. restoring with relative time and penalize flaggers). Of course they first have to decide whether they want users who cares about the stories they submit and therefor think that non bad things getting flagged off the front page is a problem.

Then people would just submit clickbait titles such that their submission gets quick upvotes for flag immunity.

Good point -- but certainly you can agree that after a certain point threshold flagging is increasingly less valuable and should be more to simply let the mods know to take a look.

Anything is preferable, at this point, to the methods used. Perfectly good articles are getting dropped and it comes across as censorship.