For example it could be used as a notary service and as an alternative to patenting inventions.
Instead of writing down and idea and posting it to yourself you can type the idea in to a file, create a SHA1 hash of it and put it in the block chain. If at a later stage someone tries to steal your idea you can prove that it originated with you, or at least that you recorded it first.
Wow, I was looking for something like this!
I'm definitely going to do this.
I want to make some predictions about the future and store my will in the blockchain!
In which ways is it different than making a transaction and putting the text in a label? If I'm not mistaken both are inside the blockchain
Well, if you hash a message with SHA256, you'll get a private key of with you can generate a public key (bitaddress.org)
When you send some satoshis to that address, it is locked in the blockchain but nowbody knows the message yet.
Basically it is the same as a brainwallet.
I don't know about the message in a label because I never used it but since it is visible it works differently