You could, sure, but that depends on Twitter still being around if/when the case comes to court. The blockchain, being independently held and cross-verified at every node of the network, is more reliable in this regard.
I wonder what the odds are that the current block-chains will be active in 70 years? Probably lower than the likelihood that all public tweets are recorded in the library of congress or some similar institution.
Does a 60 year old archive of a block-chain that "lived" for 15 years of any value? It could probably be "faked" with a cluster of machines and some time?
At any rate for things like a paper, we already have the ability to go and get a document notarized somewhere -- and that has much more legal precedent than some clever mathematical hack.
Would be interesting to see law firms offer "adding to and helping maintain" a block chain as a supplement to regular notary service though.
[ed: Ah, contributing to the slashdotifization of hn. I see that the article is about a company that tries to do this. I still wonder about what happens if/when "everyone" moves away from (the current) bitcoin (chain) to a new protocol. I suppose it could be "easy" to log the current state of the old chain, in a new chain. Would make verification more complicated though?].
Another possibility when it's clear that another coin is surpassing Bitcoin is to "register" the Bitcoin blockchain in the new blockchain, just store into the new blockchain a copy of the current sha1. (Or a harder hash of all the blockchain, to eliminate the possibility of collisions found with faster machines.)
Is it? That question is just as open as it is for Twitter, and given the order of magnitude differences in inefficiency of a blockchain versus Twitter there still remains the question of why people would burn electricity just to act as DRM for corporate trademarks.
This is an interesting technical hack in the same way as using Emscripten to run a GameBoy emulator in a Linux running on a toaster perhaps, but no one buys toasters for the purpose of playing GameBoy games.
Maybe there could be a "Platform Test Coin" to beta test all these far out ideas, then spin off the successful projects to their own independent alt coins?
Even assuming the BTC network can handle a lot of bloat, wouldn't it be cheaper for users of XYZ platform to use a (less expensive) altcoin blockchain? I'm not an expert on inserting data into a blockchain, just thinking out loud here.