RE: Blockchain based stackoverflow
I don't think there is much of an issue with sites like Stackoverflow shutting down.
Think of the forum environment like a forest, when one giant tree falls (Stackoverflow) it allows for, and promotes the growth of other trees that were blocked from growing because they didn't get enough light.
The web is not a static world, just like a forest. Blockchains are no different.
Blockchains are like the brambles - blackberry etc. They spread far and wide and can be almost impossible to eradicate completely.
Notice I said almost impossible. Blockchains may be difficult to shut down, but it is not impossible to do. In fact I think we will see an attack that will do exactly this in the near future.
I don't see the current blockchain technology as the answer to all our problems. It is just the beginning of an evolutionary paradigm that will look nothing like it does now, in a few years time.
That's the exciting bit.