I think it's not really viable to expect people to install a browser extension that interferes with their login sessions to sensitive websites, but if this tech

I think it's not really viable to expect people to install a browser extension that interferes with their login sessions to sensitive websites, but if this technology was built into browsers it could be very interesting. The UX might be a little awkward, but you could have a "Notarised documents" location under "Save Page As" which stores the current page with an accompanying file containing the notary details. Then you'd be able to upload these documents via a web interface to a smart contract. There would have to be some way to cryptographically blind the connection between the distributed ID and these documents, though, as the documents would be plaintext and contain actual usernames.