It's often called a taint analysis, but since the coins all mix together as they are spent, and there are so many addresses in between, it can become difficult to define exact connections, and its impossible for the tool to know which endpoints you want. Therefore, the analysis traces backwards and tells you what percentage of the coins came from various addresses.
For example:
1HWqMzw1jfpXb3xyuUZ4uWXY4tqL2cW47J only ever received newly mined coins, so
its taint analysis doesn't show any prior addresses:
https://blockchain.info/taint/1HWqMzw1jfpXb3xyuUZ4uWXY4tqL2cW47JMeanwhile:
1N1mCewkJPzYzxiacd7UrQ8hThtq9FJxH3 received all the newly mined coins from 20 different addresses, and never recieved any coins from anywhere else, so
its taint analysis shows 20 prior addresses and 2.5% of the coins coming from each address:
https://blockchain.info/taint/1N1mCewkJPzYzxiacd7UrQ8hThtq9FJxH3Then:
1LMcXZXujLqkfCxXQzN8E51EzJiRwMqbjU received half of the coins that 1N1mCewkJPzYzxiacd7UrQ8hThtq9FJxH3 received, so
its taint analysis shows 1N1mCewkJPzYzxiacd7UrQ8hThtq9FJxH3 at 50% and also shows all of the addresses that 1N1mCewkJPzYzxiacd7UrQ8hThtq9FJxH3 received from at 2.5% each:
https://blockchain.info/taint/1LMcXZXujLqkfCxXQzN8E51EzJiRwMqbjUTaint analysis looks backwards at the source of the bitcoins that an address has received. You can go in the other direction with the blockchain.info tree chart.
https://blockchain.info/tree/240049This indicates that 50 bitcoins were mined and they were all sent to 1HWqMzw1jfpXb3xyuUZ4uWXY4tqL2cW47J
If you click on the 1HWqMzw1jfpXb3xyuUZ4uWXY4tqL2cW47J circle, you can see that those 50 BTC were then sent to 1N1mCewkJPzYzxiacd7UrQ8hThtq9FJxH3 which was then holding a total of 1000 BTC.
If you click on the 1N1mCewkJPzYzxiacd7UrQ8hThtq9FJxH3 circle, you can then see that those 1000 BTC were split and sent to 6 different addresses.
You can continue your way down the tree all the way to the current location of each of those pieces of coins if you have the time and patience.