Hi and thanks to all for chipping in with your input but..
I must say I'm still missing something - and I'm happy to say, maybe something has clicked yet for me..
I know the blockchain verifies that a trail of events (transactions) remains true, this is it's purpose. If you read the article on the bitcoin wiki (
https://en.bitcoin.it/wiki/Secure_Trading) it says that "
Bitcoin users may want to trade bitcoin directly with each other in what is known as an over-the-counter market", this suggests that I can pass a bitcoin directly from my wallet to your wallet without the blockchain. Or when the say "
directly" do they mean by-passing exchanges etc?
This article you are referring to seems to be a little dated, as nowadays you're better off just buying Bitcoin on exchanges such as Bitstamp or Kraken. P2P trades are nowadays mostly done using Bitcoin.de or LocalBitcoins, which take care of escrow for you.
Note that trading Bitcoin is something different from sending a Bitcoin transaction. Sending a Bitcoin transaction is just that, a transaction as described in the posts above. Trading involves you exchanging bitcoins for goods or services or other currencies, such as USD or EUR. How the goods, services and other currencies are provided depends on the trade or trading platform (eg. it could be a wire transfer, it could be handing over cash). The bitcoins themselves however will still be send over the blockchain. You will know that you succesfully received your bitcoins when your wallet shows an incoming transaction with at least 1 confirmation. Recommendation being 6 confirmations, however 1 confirmation should suffice for normal everyday transactions.
In other words: Sending a Bitcoin transaction is like handing over cash. Trading bitcoin is like you handing over cash and receiving a piece of gum (or the other way round). The blockchain only takes care of handing over the cash. The tricky part is making sure that the gum is actually received. This has nothing to do with Bitcoin and that's were exchanges come into play.