What's changed? The interface and primitives available for building applications. Rather than having to create a blockchain, we can _use_ a blockchain to do the timestamping.
Our insight is that this is still too hard to have quick access to use the blockchain meaningfully. So this service is a wrapper around those blockchain/cryptography primitives making it easy to create and lookup. It's the indexing part that can make the difference between a useful app in theory and in practice. In theory anyone could read the blockchain and create their own index from certain data on it...in practice that's more work than most will do... hence this kind of service.
Our insight is that this is still too hard to have quick access to use the blockchain meaningfully. So this service is a wrapper around those blockchain/cryptography primitives making it easy to create and lookup. It's the indexing part that can make the difference between a useful app in theory and in practice. In theory anyone could read the blockchain and create their own index from certain data on it...in practice that's more work than most will do... hence this kind of service.