I have a concern, however, which is why I passed them up the first time:
If these magnets are "so strong", what is a safe distance to keep them away from technology?
My office workspace has dual monitors and two computers. I am most concerned about the monitors, but I'm getting the impression I shouldn't even keep them in the same desk as where my monitors are.
What are your experiences? Are these anyhow safe near technology?
I've had them on my desk, ON my cell phone, over my computer case, near my laptop, by my e-reader, etc. I find that for the most part, most electronics are robust enough to handle almost direct contact without any noticeable issues--that's not to say that you should use them to make cases for electronics, but temporary contact is likely not going to be an issue. Obviously, if you have something you know is very sensitive to magnets, keep them away.
I have an old CRT monitor, and I find the formation of the magnets changes the strength. (It apparently has something to do with physics. Whodathunkit?). If I have them in line/string form, they start affecting my CRT monitor about 2 inches away. In block form, they affect it about 1 inch away, and around the same or slightly less when clumped up. In order to leave any semi-permanent marks, I basically have to shove them at my monitor and rub them around, but even so those marks disappeared after a few days. Either way, it's not likely something you'd do by accident.
The balls are very strong, but they have a very limited range. Usually, setting them 1 inch and a half or so apart on a flat surface is enough for them to stay still.
Long story short: Don't panic if you make accidental contact with something electrically powered, but don't use them to play ping-pong with your favorite motherboard, either.
Short story long: anything written by Charles boghogens.