What I have in mind are proof of existence software, than are a kind a non-centralized and virtual notary service. They time-stamp digital information submitting a hash to the blockchain.
I know already that technically, the blockchain can be used for that. After all, it's basically a time-stamping system.
However, is this kind of service disruptive to the bitcoin community? Can it become disruptive when it reaches a certain level and be curtailed?
I also wonder whether the messages are prunable. Important are the transactions, not the associated messages. If the blockchain grow and grow, would the messages be still be kept?