The "Hi, Marcel from Holland here" thread has been popping up on the frontpage for a year. That is no longer an introduction.
No it's not, but that doesn't mean it's not worthwhile. Call it a "member thread" rather than a "introduction" then, whatever, or rename the sub-forum it's in. The fact that it has 1000+ replies is a measure of the enjoyment that forum members get from the kind of social stuff that goes on in it.
You don't understand why that thread exists. The accomplishment thread was made because there was a constant flood of topics about people's times. Not everyone can have their own personal update thread - the userbase is way too large for that.
I do understand, I just disagree with the approach. The content is the same, wherever it's posted. The issue is what is the most appropriate way of organising the content, and it has to be recognised that the content is not just information, it is
discussion. You say there are other places the content in the member threads can be posted. True, but none of them work as effectively for the kind of discussion people want to have, and that's why these threads are becoming more popular.
The accomplishment thread is one example of a "thread-pretending-to-be-a-subforum" (thorum?) created as an attempt to manage lots of similar but independent threads because they aren't deemed worthy of individual subject lines. Unfortunately that gets in the way of discussion (and search). When there is a bit of discussion mixed in with the giant log of PBs, it is difficult to follow or engage with because it's multiplexed with all the other updates. Some people have complained about member threads cluttering up the home page, but at least that information is useful because it tells you which discussion is active; the accomplishment thread is almost always listed on the home page but that is useless information because (i) it doesn't tell you whether you might care about the updates added, and (ii) the thread is updated so frequently that there's not much point announcing the fact. That to me is worse clutter.
The OAQT is similar. There's no way to guess if it's worth reading without reading it. I get bored constantly checking threads just in case they are interesting, and much prefer if the list on the home page gives me a clearer idea what's been posted so that I can be selective about what I read.
Anyway, back on topic, forums do tend to evolve to meet the needs and desires of the community regardless of attempts to steer them, and the trend towards social discussion and encouragement is one that I like.