It would be very interesting if the Datacoin Browser had an EDIT facility, where a transaction could be indicated as an "edit" of a previous transaction. In that way the browser could show updated versions of transactions and their files. Then the raw data on the blockchain could be shown as newspapers, tweets, social media posts etc. All uncensorable.
This would effectively implement the "sidechains" that oocook5u talked about.
EDIT: Oops, I see this is already part of the envelope rules (#4).
Yes, updates are already possible. Datacoin Browser currently shows the newest valid update if you request the original tx (or any tx in the update chain).
One of my planned features includes an history function.
Something like:
/dtc/lsrpc/listhistory/TXHASH
/dtc/lsrpc/gethistory/TXHASH
Which lets you access a specific update (or the original tx)