Permadoc is a free utility for publishing documents on the Ethereum blockchain and viewing them from a browser. All documents are public and will last as long as the blockchain does. Publishing takes a one time fee that varies based on how busy the network is. This doc was about $0.03 to publish.
You pay once to publish forever. It can never be censored, taken down, or removed (we can remove from the site, but not the chain). It also can't be edited, so you can trust the timestamp.
A blockchain is a list of transactions hosted and agreed upon across many servers distributed all over the world. There's some cool math and game theory (thanks Satoshi!), that mostly guarantees that every transaction is remembered forever and never changed. Each transaction can have a small piece of data associated with it. Permadoc uses this to store your document in an immutable transaction on the blockchain.
Good ideas:
Bad ideas:
IDK, but please be nice!