I have a question about whether there is a mechanism which deletes posts from the steem blockchain after a number of years.
No. What was written to the blockchain stays in the blockchain.
In 100 years, if steem continues to exist do you think that those records will continue to be there?
All you need for that is stakeholders to be still interested in Steem. In fact, at least one would do the thing (decentralization suffers, but the blockchain can survive running).
Wish me a good health. I'll do my best to be there and keep the Steem running. (As long as the doctors would do the same for me).
I wrote about the subject of AI based on our digital DNA a few months ago. This way even though our bodies might be gone, our personalities represented in the posts we make will act as the theme for personality constructs. If you go to my steemhost profile and search for Bina you can see the two articles I discussed the topic.
This is a blatant attempt to show the value of steemhost.
Good post