One thing that has always intrigued me was the way email services (Yahoo, hotmail, whatever) sort through your mail and determine what is junk and goes to the 'Bulk' folder.

I have two things I get daily in my email: Campus News and a Word of the Day (I think it's through Webster). On the large scale, I open maybe, maybe 1 in 10 of the Campus News - deleting the rest. However, I always open my WotD and read it.

A few days ago Yahoo!, being the genius mail provider it is, began sending my WotD (which I always read) to my junk mail, yet it leaves my Campus News in the regular folder. Even more odd is the fact I've been getting (and rarely opening) Campus News for 3 years and WotD for maybe 3 months.

So sure, I can click "Not Spam" on the WotD and it will probably fix it, but the logic of the sorting program seems a bit messed up in the first place. I don't think it will ever be perfected.