I'm not familiar with pastebin.com, I'm not sure if it supports editing or versioning. This could be a trick to solve in blockchain.
As an alternative idea for storing (since you don't need to sort as trending/hot or else) one of sam's solutions which he used for @finallycomments. These can be stored under a main post as comments without needing any extra server costs.
Another concern is privacy, these can't be shared to specific people. (unless you find a solution for it:D)
There is no privacy - Everything is transparent :D