Three new things walked into a bar…

Walt: Three new things walked into a bar…
Here’s a simple check on your perceptions. Which of the following do you consider to be successful–either currently or as some form of inevitable game-changer in the near future?
* Blu-ray Disc
* FriendFeed
* Kindle
Now, let’s put it another way: Which of these has greater actual marketplace impact–that is, which is actually used by the most people?