From the little I understand, you used to use many computers usually with many video cards (better at parallel processes I think) to "mine" bitcoins from intensive hashing of data. It used to be profitable to mine, but now hardware costs plus the cost of electricity for running and cooling in most places make mining unprofitable. They have since tried to move to using Field Programmable Gate Arrays it seems. There are a ton of used up video cards used to mine for sale on eBay.
https://www.weusecoins.com/en/mining-guide
I saw a plugin on Reddit the other day that I believe was allowing users who had it set up to "tip" people with percents of bitcoins using a command in their comment they both had their accounts connected to their Reddit profile, so its getting faster and looser with the rules. I don't predict it will be a trusted form of currency much longer from all the hacking and viruses targeting bitcoin users combined with its growing attention.