Just like a regular wallet. It holds access to money. A regular wallet might have Bank notes, uncashed checks, credit and debit cards. A BitCoin wallet holds, well BitCoins. If you drop your wallet in say the luggage claim at a large metropolitan airport. Odds of you getting your physical wallet back (let alone intact) is pretty slim. Same goes for your wallet if you put it up in plain sight on the internet. You need to protect your wallet from loss and theft. If it's stolen or lost, you can't call the bank to freeze transactions from your wallet, you can't get a new wallet with your old coins in it. It's just gone. No one is coming to your rescue. So, what types of wallets exist? Well, we have Brain wallets, Paper wallets, Computer based wallets, mobile phone wallets, and cloud wallets. Choices, choices. In subsequent posts in this thread, I'm going to go over each of them individually. Oh, and just like eggs, you shouldn't keep them all in one wallet.