Missing 98%

[Kazimir]

Assuming that most of long chains are produced by mixers,

Seems like a far stretch. Normal usage of HD Wallets would typically create long (and continuously growing) chains. And considering that almost all wallets are HD nowadays, I'd say this accounts for normal, every day usage of Bitcoin for regular payments.

The 98% should be regular transactions like job payments, Pool payments for miners, crypto exchanges, shopping, mining equipment purchases, betting and gambling.

The 1% black market is nothing to consider.

Exactly. And if 98-99% is legit, and only 1% is involved in crime related transactions, then the FBI, NSA, and other TLAs are obviously chasing the wrong currency! The crime rate is far, FAR higher with the Dollar and Euro. They should be chasing the fiat market instead, it's full of malicious scum! BitLicense should be focused on Dollar-businesses instead of crypto!

[jl2012]

most of those "volume" could just be change. You have 10000BTC and send 0.5BTC out and 9999.5BTC back to yourself, and you have generated a transaction volume of 10000BTC.

[Kprawn]

If you believe the Press & Shills it would more likely look like this :

40% Child Porn
30% Drugs
20% Money Laundering
5%   Other criminal actions {Tax evasion; unregulated gambling etc. etc.}
5%   Legal Trade.
But, we all know.... most of these people are on crack and have a hidden agenda, and are puppets for the masters... So it's more likely something like this :

80% Legal Trade
20% Child Porn / Drugs / Money Laundering / Tax evasion / Gambling etc...

* Disclaimer : My own opinion 

[Wary]

most of those "volume" could just be change. You have 10000BTC and send 0.5BTC out and 9999.5BTC back to yourself, and you have generated a transaction volume of 10000BTC.

Interesting idea! If you are right, then we can say that the mystery is solved. Hovewer, it depends on how the people on blockchain.net calculate their "estimated USD volume". The simplest way to exclude the change is to include only the smaller output of transaction (if it not zero) and ignore the bigger one. Unfortunately, I don't know if they did it.

[RustyNomad]

most of those "volume" could just be change. You have 10000BTC and send 0.5BTC out and 9999.5BTC back to yourself, and you have generated a transaction volume of 10000BTC.

Interesting idea! If you are right, then we can say that the mystery is solved. Hovewer, it depends on how the people on blockchain.net calculate their "estimated USD volume". The simplest way to exclude the change is to include only the smaller output of transaction (if it not zero) and ignore the bigger one. Unfortunately, I don't know if they did it.

You cannot really do that as transactions can both ways meaning, sometimes the larger amount will be change going back to the wallet and at other times it might be the smaller amount. I don't think there is way to actually know which amount will be the transaction and which will be the change.

[Wary]

most of those "volume" could just be change. You have 10000BTC and send 0.5BTC out and 9999.5BTC back to yourself, and you have generated a transaction volume of 10000BTC.

Interesting idea! If you are right, then we can say that the mystery is solved. Hovewer, it depends on how the people on blockchain.net calculate their "estimated USD volume". The simplest way to exclude the change is to include only the smaller output of transaction (if it not zero) and ignore the bigger one. Unfortunately, I don't know if they did it.

You cannot really do that as transactions can both ways meaning, sometimes the larger amount will be change going back to the wallet and at other times it might be the smaller amount. I don't think there is way to actually know which amount will be the transaction and which will be the change.

You are right, but all we need is an estimate. If the most common pattern of bitcoin usage is "spend smaller part", the estimate won't be too wrong.

[alani123]

I think that coin mixing could play a big part in this. Y'know people 'washing' coins in order to hide their origin. Transactions with the same sender and recipient (in the end of the trail)with the sole purpose of making finding the origin of the coins harder.

[jl2012]

most of those "volume" could just be change. You have 10000BTC and send 0.5BTC out and 9999.5BTC back to yourself, and you have generated a transaction volume of 10000BTC.

Interesting idea! If you are right, then we can say that the mystery is solved. Hovewer, it depends on how the people on blockchain.net calculate their "estimated USD volume". The simplest way to exclude the change is to include only the smaller output of transaction (if it not zero) and ignore the bigger one. Unfortunately, I don't know if they did it.

bc.info has a track record of providing inaccurate info. Don't take it too seriously.

In the early versions, bitcoind always put the change as the last output.