Yes, a few days ago I promised a further report on various things, including the effects of alternate start points in my dataset and expiry on the train_on_everything and train_on_almost_everything regimes. Unfortunately, all I have at the moment is some preliminary results and a big heap of frustration pointed at my computer. 1. There doesn't appear to be anything particularly magical about 120 days after start. Rotating my data forward or backward 80 days shows that (a) there was a particular event/change in my data at about 120 days after I started collecting that affects the accuracy of further classifications, and (b) the general curve of getting better for a few months then decaying for the rest of time still holds even when the data is rotated... but the curve is not as distinct when not reinforced by (a). 2. Expiry (as I implemented it) appears to be a very bad thing for long-term TOAE. I implemented it to expire trained messages after 120 days, without completely rebuilding the classifier. This resulted in significantly degraded accuracy after about 250 days, though that may just be due to an ever increasing spam/ham imbalance. There was a sharp drop in the amount of spam training for about 30 days after the initial expiry date, and then a net spam training rate about equivalent to non-expiring TOAE until the "latest windows update" worm, after which spam training about doubled the non-expiry version. This seems to show that spam mutation has a stong effect on 4-month expiry for TOAE. On the other hand, net ham training was fairly consistently slightly negative after expiry commenced, showing that once it got a good idea of what ham was and threw out the oddballs that got trained on initially, it didn't need much categorize ham. By the end of the mess (at 418 days) the spam:ham ratio was over 15:1, and the unsure rate was around 3% (compared to non-expiring with 4.5:1 and 1%). 3. Expiry for TOE seems neutral (compared to non-expiring TOE), to the best of my ability to eyeball the three runs that actually completed. The graphs I have are at: http://www.wolfskeep.com/~popiel/spambayes/plots/expire.html My primary machine (cashew.wolfskeep.com) unfortunately doesn't seem have the capability to maintain reliable service while running these tests anymore. They're just too big, and it doesn't have the memory/CPU to do everything all at once (including running my web server, a mysql engine, my mail feed, etc.). Plus, it appears that Linux 2.4.18 doesn't take too kindly to multiple processes trying to access/manipulate a single directory with over 100,000 files in it; anything that touches that directory after things have started going wonky just hangs in disk-wait. I'm suspecting a deadlock in the filesystem layer on extended directory operations... probably due to not enough file cache (see my memory problems) to hold the entire structure at once. I haven't poked deep enough into the ext2 drivers to be sure, though. Anyway, I'm not going to be able to do all that much until I get this straightened out. I'll add graphs and stuff to the wiki as I have time, but that's likely to be all for a bit... - Alex