Yes, me and a friend from the robotics club at school tried it the other year (everyone else in the room was pretty annoyed) it works but it's very finicky:
Your sound card is going to work best in some small band of frequencies (around 3khz if I remember) the mark and space tones have to be pretty far apart and the volume has to be turned up pretty high.
Turning the baud rate up increases your error rate so unless you're including error correction in your transmission that has to be pretty low.
Yup, you can run a speaker cable between mic/line-in and speaker/line-out to pretty good effect. When I'm working on radio protocols I usually use this if I don't feel like setting up a pair of radios.
This article is garbage by the third sentence. Only "evidence" Khufu built the pyramid is the forged cartouche in the "relieving chamber" of the "King's chamber." The entire history is predicated on its supposed authenticity.
The readme shows roughly 4.5 Mh/s which might get you maybe $10/month if you're lucky.
A g2.2xlarge will cost you $0.65/hour.
So, no, it's not anywhere remotely close to profitable -- unless you've stolen some AWS credentials or (like what's apparently happening here) you get others to mine for you and eat the AWS costs.
