Originally Posted by
nethwen:
“I know this is a long shot... but I wonder if Mr Moffat will now show us how Sherlock survived the fall.
ETA: Maybe not.”
I took it as confirming that the third explanation, with what's her name providing a body, was actually the true one. A lot of people were denying that.
Originally Posted by
pedrok:
“But all that happened, going by your explanation on the other thread (thanks for that) is that Holmes now knows Moriarty is dead. But he can't be as Holmes says something about knowing what he will do next 
So, if he is dead, what can he do next?”
We saw Moriarty on TV. So presumably that was a recording that Moriarty prepared before he died, to be released in the event of his death. Perhaps on a dead-man's switch - in other words, perhaps it released automatically unless he did something to postpone it each day.
Anyway, if he'd left behind the recording and the where-withal to get it broadcast, he can have left other timed automated activities, too. Most likely internet-based, like releasing a computer virus, but there could also be physical time-bombs, perhaps releasing a biological virus. Since Moriarty is dead, he doesn't care if he makes the planet unliveable for everyone else. (Although I suspect he'd want some people left alive to remember him.)