How does that make sense? Using that logic wouldnt i be able to randomly buy a bit coin and see the whole history of it...
Yep. Of course, there are no actual "coins", that is just a term used to make it easier for the average person to talk about. But what represents the value of transactions in the blockchain ("inputs" and "outputs") can be traced back from address to address all the way back to when it first came into existence with a miner.
Now multiple inputs get joined together into fewer (or more) outputs so you end up with quite a tree of connections after a while, but if you want to follow it from address to address the information is all there. The blockchain is a record of every valid bitcoin transaction that has ever existed.
Confused as the person just above you is against that...
Bitexchange was talking about ways to avoid connecting your identity to your bitcoin address. Bitexchange was also talking about ways to keep your bitcoin addresses from being linked to each other if you have multiple addresses.
I was answering your question about seeing the "whole history" of the bitcoin that you own. What I said is that you can see the history of bitcoin addresses that the bitcoin value has passed through and that the blockchain has the entire history of every bitcoin transaction that has ever occured.
However, the blockchain uses bitcoin addresses to identify the transaction. If you don't know who's bitcoin address it is, then you don't know the identity of the person who engaged in the transaction. So, as Bitexchange suggests, if you can obtain your bitcoin in an anonymous manner, and spend them in an anonymous manner, then people will be able to tell how much bitcoin was received and spent, but they won't know who the person is that received and spent the bitcoin with the address.
Almost complete anonymity is possible if you are very careful about how you receive and spend your bitcoin. Slightly less anonymity can be maintained by following some general guidelines. If you are really careless about it, then you can end up completely eliminating your anonymity. It really depends on who you are trying to hide your activity from, and how important it is that you remain anonymous.
