What exactly is the reason that every link to a discourse post has a u=username at the end? Since the links are functional without, I suppose the idea is some sort of tracking. But for what purpose and where/how does they become tangible in some statistics? Differently put: if I remove my username from manually pasted links, what am I missing?
You are correct that the
u=username parameter is used for tracking. We use it for tracking how popular shared links were from various users. If you want to anonymize the share you can remove the parameter and we won’t know who shared it.
We use it for badges, for example this one, to reward users who bring many views to the forum.
Okay, that makes sense. Most of the time, I use those links within the forum (linking one post with another) and I didn’t really see the point there. But for external links it makes sense.