None of the pizza can be eaten unless you have two of the three slices. If you put two of the slices together, the third slice will magically appear, completing the pizza. So it doesn't matter if someone runs off with the slice they control. One slice is useless by itself. They also keep all the slices in different countries.

Can you accurately predict the money supply growth of an African currency? Does any African currency have properties that make it far superior to dollars? Can you encrypt your cash so that thieves don't get anything if they steal your wallet? Can you carry huge amounts of your cash across an international border? Does your cash work just as well in other countries? Is your cash worth 300% more than it was in January?

In the last 3 months: money supply expansion halved, number of merchants doubled, wordpress accepted it, US facing pokersite leaks they will accept it, largest gambling site profit up hundreds of %

If this stuff happened to any company, its share price would double.

Also, in the last year:
Network transaction fees per day are up 1100% from 4 to 48
Explosion in p2p exchanges for cash or bank transfers on sites like localbitcoins
Coinlab and BitPay each got 500k in venture capital. Coinbase got 100k.
Bitcoin Foundation Launched in September 2012
ponzi worth between 250k and 5mil collapsed
BitInstant lets you buy bitcoins at walmart, 7-11, and CVS
Silk Road is doing at least 2mil/month. Forum usage up hundreds of percent over last year.
A $10mil company will be releasing the BitcoinCard this year at the Vienna Bitcoin Conference. The Russian founders say 5 years of research have gone into this technology allowing a super-low-power credit card sized device to send texts, bitcoins, login info, and consumer data through an ad-hoc network instead of cell towers, at a card cost of only $10-$25
SatoshiDice has shown the potential of the bitcoin gambling market by earning $600k, including 17,266 bitcoins in December
Many companies in the bitcoin community have gone public.

Read the bitcoin FAQ: https://en.bitcoin.it/wiki/FAQ
If you still have concerns, see if they are addressed in the "myths" section: https://en.bitcoin.it/wiki/Myths

Thanks for the Jitsi/Retroshare tip. Nothing appears for "encrypted voip" "encrypt/secure voice call" etc on google. Google trying to hide it?

Backing is for stuff that is not valuable in its own right, such as pieces of paper with pictures of presidents on them. Bitcoin is valuable for its properties, and it has numerous huge advantages over the fiat competition. Notice that these are not tiny advantages, but a large number of giant leaps forward:

Decentralised and free from control
Always running 24/7
International
No/low fees
New privacy model
Transparent system
Divisible
Secure
Fast transfers
No chargebacks
Environmentally friendly / efficient
Digital

I can spend them on over 2500 websites, donate $1 to wikileaks with no fee, instantly deposit/withdraw from poker/sportsbooks, get 5% off on amazon purchases, and do sub $1000 currency conversions for less than any other method. The IRS doesn't know about it, no one can sue me to take it, my wife doesn't get half of it in a divorce, and I don't have to worry about it being inflated away by the government. It increased in value by 1,750% in 2011 and 186% last year, more than any other asset class. This is a radically superior money compared to pieces of paper and gold, even if you only count what it can do right now, and this is just the beginning. All kinds of cool stuff is getting built into the protocol. The future will show the real potential of this disruptive technology.

More detail on these points at: http://bitcoinmedia.com/bulleted-advantages/

Of course Virtual Currencies will have a "negative impact on the reputation of central banks." Virtual Currencies like bitcoin have numerous huge advantages over the fiat competition. Notice that these are not tiny advantages, but a large number of giant leaps forward:

Decentralised and free from control
Always running 24/7
International
No/low fees
New privacy model
Transparent system
Divisible
Secure
Fast transfers
No chargebacks
Environmentally friendly / efficient
Digital

I can spend them on over 1500 websites, donate $1 to wikileaks with no fee, instantly deposit/withdraw from poker/sportsbooks, get 5% off on amazon purchases, and do sub $1000 currency conversions for less than any other method. The IRS doesn't know about it, no one can sue me to take it, my wife doesn't get half of it in a divorce, and I don't have to worry about it being inflated away by the government. It increased in value by 1,750% last year, more than any other asset class, and this year it is up over 135%. This is a radically superior money compared to pieces of paper and gold, even if you only count what it can do right now, and this is just the beginning. The future will show the real potential of this disruptive technology. Central banks and fiat will be a thing of the past.

More detail on these points at: http://bitcoinmedia.com/bulleted-advantages/

You can call it a feature. It is a feature that most of the world has rejected because of the huge amount of fraud it invites. It is a feature with a gaping security hole. It is a really expensive feature for consumers.

The US is a quarter the world's card volume, and half of the world's card fraud. Credit card security is a joke by design. You have to trust every single merchant you buy from with your account details. And even though the cost is hidden from us because the merchants get billed for the fraud, we are the ones paying for this through higher prices. Here's an article about reversible vs non-reversible payment methods and how credit cards aren't even viable in most of the world due to fraud: http://bitcoinmagazine.net/bitcoin-and-consumer-economies-in-the-non-western-world Bitcoin fixes this gaping security hole by the way.

You are correct. My statement should read "New privacy model", not just "privacy". The protocol is indeed not private, but public.

"Privacy" means nothing in the protocol links the coins to my name. Notice that the article author's have no idea who owns the 90k bitcoins that were apparently laundered poorly. "Digital" means I can back up my cash and have several encrypted copies of it so it can't be stolen.