@75gmck25,
THAT'S RIGHT!! I found the same thing out when I took a old HDD apart, the old 3"x5" size, just to see what was inside. Man, those little suckers are super strong. Don't lay them down on a flat piece of metal. I hope you've got strong fingers 'cause you're going to need them to lift those things off.
@AuroraGirl, Yes. Those magnets are what laid the data onto the platter's that are inside, well, and other electronic stuff in there to. There are disc shaped platters inside. The higher the gigabit capacity the more platters are in them. The platters spin between those magnets, and I have no idea how they work. That's all I was able to guess at just looking at the parts inside.
When I worked for the airlines we had some scrap instruments, one being a "artificial horizon" That thing had a big magnet in it. I use it to find screws, and whatever else I've dropped outside the shop. Mostly looking for nails and bits and pieces of metal. I also use it to magnetize screw driver tips. It's great for that because it's a "horse shoe" shaped magnet. Just drag the tip over the ends of the horse shoe and you won't be dropping screws anymore when you are having to put a screw into a place you have to reach for.