Notebooks on Ethereum blockchain. Carved in stone.
Available on mainnet and Ropsten testnet.
Make new tablet at tablet factory: new tablet will be deployed at a separate address (add tip if you like it ;-). You'll become the owner and the only scribe of this tablet.
You can add records to your tablet, like in a notebook. All records are stored in your own contract at Ethereum blockchain. There is no delete record option. So, everything will remain in the network while Ethereum exists. Remember, all records are public!
In the settings you can add and remove scribes of your tablet. Only tablet owner can do this.
Finally, you can transfer ownership of a tablet to another account.