> Expensive?
Yes, I meant not free. Opentimestamps uses bitcoin transactions, which have fees, so someone has to pay. Now donations pay for it.
> I don't know what you mean by 'commitment at key creation'
That someone has to pay for opentimestamping, most likely when they create the key and publish their profile.
> The point of it would by that someone TODAY, can't start pretending to be someone who created his profile and starting posting 3 years ago
sure, that has some utility but it's not really easy to use to determine which is the "real" profile. For example in case of name-squatting or key rotations (e.g. Ben Arc multiple real profiles).
