Here's what we've got so far:
1) Major legacy bank exchange
2) Amazon.com
3) Usable software
4) Remove overhang (e.g. FBI coins)
5) Systemic/national financial instability
Here are some more:
6) Favorable regulatory change (e.g. China wises up, or India)
7) Killer app gains traction
![Cool](https://bitcointalk.org/Smileys/default/cool.gif)
Remittance network adoption curve inflects
9) ETF opens in U.S. or London
a) Leading investor takes large postion
b) National police/spies/military accumulate tactical holdings
c) Central banks accumulate strategic holdings
It would be useful to estimate pdf vs. time for these and any more suggested