Those are mostly filling in unposted articles to stop new threads starting up and instead direct to where the discussion is already happening. Because the dupes are out of control sometimes

A friend of mine had some content reach the front page maybe 6 months ago. I don't know this for 100%, but I think for cool projects that dang thinks are of interest to the community, he will post them to the front page manually some time after the original post date when (speculation here) the front page needs some interesting content. When something like this happened to him, my friend's post date got reset, but the votes and comments it may have received while it was waiting remained. This might explain the instant votes mentioned.

Nice little project, I'm glad to have seen it. Music generation stuff is always of interest to me.

edit: Saw this on another thread. Seems to line up with what I was talking about: https://news.ycombinator.com/item?id=26998308