What are the different ways the worth of bitcoin go up/down?

[Jpark]

Is it possible that people could hack your computer and delete your wallet, therefor deleting bitcoins and hurting the bitcoin economy?

[AliceWonder]

A hacker would not want to delete your wallet, but rather steal your coins.

But yes, if you don't back up your wallet and the data becomes destroyed, your coins are gone forever.
The bitcoin system doesn't know they are gone, no one knows how many coins have been lost. But you'll never be able to spend them.

back up your wallet and keep your computer secure.

[Gabi]

Yup, and they can also steal your wallet

[Jpark]

So I can duplicate my wallet and keep it on dropbox with a password?

[AliceWonder]

So I can duplicate my wallet and keep it on dropbox with a password?

You can make as many copies of your wallet as you want.

Two backups on encrypted USB thumb drives are not a bad idea (in case one thumb drive fails).
As far as dropbox or whatever, make damn sure the wallet is encrypted before using remote backup.

[Jpark]

How does that work if I'm loading and unloading the wallet? Do I have to update the wallets on those thumb drives from time to time?