Thanks for the inspiration :-)
Along the way, I realized that posting so much about STEEM wasn't really me sharing myself, and that if the blockchain were to effective shrivel up and die, all that content would be useless. If I'm sharing my journey/thoughts/questions, then those will all last (and reach) long beyond STEEM. I do think I may need to find some balance the other direction, and keep reminding folks every now and then that we're still here, and it's still free to join us.
No content is immutable - the owner is free to edit at their own leisure, I THINK. Which does offer a rather obvious means for the unscrupulous to abuse the system in the future.
Right, there's been the option to edit forever, though originally just in the first 7 days. On the back-end sites, we can see the number of edits, and what was added with each edit, but apparently the actually original content is disappearing.
I can definitely see some danger if there is no way of accessing the original content, because it allows someone to change their post, thus changing the context, and potentially making someone's comments look hateful/ignorant/etc. Changing the context post-conversation is a bit worrisome. Obviously there are other ways that people could game the system too.
The example I was looking for was the first person to be removed from TSU, as a result of violent & racist posts, and he wrote a huge piece against me and the community, but now all that can be seen are our comments.
At least with text I get to choose if I want it to disappear, I've heard nightmare stories of people's picture posts only later being available with terrible quality and dtube videos just vanishing.
Ya, the dtube thing is an issue that is easily(-ish) resolved, because the videos aren't held on the blockchain, but the IPFS, and therefore need seeders, just like a torrent. If one can't or doesn't want to run their own seed-box, they can use the @onelovedtube service to make sure their videos stick around forever.
Images likewise are not actually saved to the blockchain, simply a link to wherever they are actually hosted. I've had a few images & videos in my posts (especially research papers) get pulled down from elsewhere and had to try to track them down in order to keep my post accessible.