The site producthunt appends it to all its outgoing links. To let the websites know source of the traffic.
That's already built into HTTP with the Referer header. So what's the point?
Sometimes links will go through a number of other things (url shortener, analytics, so on) before hitting the final URL.
I think the point was that all these clicks from HN are probably misleading the analytics provider.
(Assuming the site is integrated with an analytics provider that uses that query parameter to determine the referrer.)
That is correct. This was the intention.
Some people might bookmark the link, copy it, view it later, share it, etc.
It's helpful to know that the original source of the link is producthunt (in this example).
It means that this link is misinforming chirpss that we were referred (“refered”) by producthunt.
Is that not accurate assuming the OP is from or was referred by producthunt?
The OP was, but I was referred by news.ycombinator.com.
Sure, but they are for measuring the effectiveness of marketing channels, not simply the direct referrer. They can discover the direct referrer through HTTP headers. If a marketer promotes something on Product Hunt, then somebody on Product Hunt submits it here, then you follow the link from here, it means the marketing channel that reached you was Product Hunt. It gives marketers better information in aggregate about which marketing channels are most effective.
I’m glad to understand that, though it doesn’t make me any more inclined to add any extra metadata to my web traffic.