Total Output Volume
The total value of all transaction outputs per day. This includes coins that were returned to the sender as change.
Estimated Transaction Volume
Similar to the total output volume with the addition of an algorithm which attempts to remove change from the total value. This may be a more accurate reflection of the true transaction volume.
Cost per Transaction
A chart showing miners revenue divided by the number of transactions.
Hash Rate
The estimated number of giga hashes per second (billions of hashes per second) the bitcoin network is performing.
Difficulty
A chart showing difficulty changes over time. Difficulty is a measure of how difficult it is to find a new block compared to the easiest it can ever be.
Miners Revenue
Historical chart showing (number of bitcoins mined per day + transaction fees) * market price.
Bitcoin Days Destroyed Cumulative
Bitcoin Days Destroyed is a measure of the transaction volume of Bitcoin. If someone has 100 BTC that they received a week ago and they spend it then 700 bitcoin days have been destroyed. If they take those 100BTC and send them to several addresses and then spend them then although the total transaction volume could be arbitrarily large the number of bitcoin days destroyed is still 700.