Okay, that's really interesting. I flipped over to my Vuze window, and suddenly, one of the torrents is connected to a seeder and uploading at a decent clip. I switched windows seconds after I posted. It then stopped after about a minute. There simply wouldn't've been time for anyone to have even read what I posted, but I doubt it's a coincidence that something suddenly connected and started uploading when I posted. Could it be some sort of authentication thing that only confirms a connection when I interact actively with this site? I sign into this site extremely rarely.

I'm going to hit "post" on this and see if I get a sudden flurry of activity in my Vuze window.

EDIT: Nope. I'm baffled.

I've made all the changes in the earlier-referenced thread. Although I no longer get the scrape errors, I've found that almost no leechers will stay connected for more than a second or two. I'm currently seeding a couple of torrents that I know have leechers, but it's extremely rare that any connection is maintained or data gets transferred.

If I manually update the tracker for the torrent, I'll get one or two extremely brief connections that almost immediately disconnect. I also noticed that one of those torrents seems to have a leecher permanently listed. The other has about fourteen or so leechers that haven't downloaded for days.

It seems any attempt to improve my ratio by downloading something with a lot of leechers is destined to fail. I have no upload or download problems with any site except this one.