I'm using the BlockChain.info online wallet. Are you saying Bitcoin-Qt sends the BTC from a different address and thus changes your address every time a transaction is done? That's crazy..
With Bitcoin-Qt, you don't have "an address", you have a wallet. You can create as many receiving addresses as you want in that wallet, and give those out for others to send bitcoins to your wallet. You have no control over which of these bitcoins are used when you send bitcoins somewhere. The wallet takes care of all that for you. Every transaction sends some bitcoins back to your wallet at a new address that the wallet keeps track of, but that is not shown to you, since you don't need it.
For your final note, "the bitcoin addresses".. Does that refer to the address that sent them to me? Why would it store that? Shouldn't that be available on the block chain and thus unnecessary to store?
No, that refers to the list of bitcoin addresses that you create in your wallet to receive bitcoins. The wallet needs to store these addresses so it can show them to you so you can give them out to others that want to send you bitcoins.
This whole wallet situation is enormously confusing for new users and is a massive barrier to entry. I can't see BTC being adopted mainstream when it's this difficult to work through how to take care of your wallet and protect your money.
Yes. At this point bitcoin is still in its infancy. It will be interesting to see if it ever reaches mainstream use or if it just ends up a failed experiment, but if it is going to be successful long term, there is a lot of infrastructure that is still needed.
Is there an in depth article explaining how wallets work? I've read several short articles at various websites online, but none of them go deep enough to truly understand how the system works. Someone saying here that you can lose 99 BTC by using the wrong backup file is very confusing and makes no sense to me.
Each wallet works a bit differently and has its own "quirks". They are all created by volunteers with no oversight beyond the interests and desires of the creator. Over time, through competition and other market forces wallets will be improved and newer better wallets will be created. Today's web browsers have very little in common with the web browsers from 1992. Feel free to learn about the wallets and write your own article and/or review.
Thanks for spending the time explaining a little bit.
No problem. I'll do what I can to answer as many questions as you have. The more we all understand about the wallets, the easier it is to choose for ourselves and recommend for others which is best for each person's individual needs. I'm not much good at writing up well structured usable documentation, but I've got a pretty good understanding of most of the popular wallets out there and do a half-way-decent job of explaining in a conversational manner.