Mining pools create a lot of transactions with, arguably, no economic value. When a pool earns one Ether, it’s recorded on the blockchain. When the collective distributes fractions of that coin to its members, the disbursements create multiple transactions. Distributions from mining pools to their members accounted for 19 percent of Ethereum transactions, Galka said.

Spam is a huge problem as well. On Ethereum, a slew of obscure tokens are showing high trading volumes and clogging up the network. In one instance, FCoin said that each new user who registers and deposits a token can vote for that token to be listed on its exchange. As a result, many people are creating multiple accounts to increase votes for tokens to be listed, Galka said. He figures that spam activities add up to 19 percent of transactions.

With other coins, various actors have been known to spoof transaction volume, or flood the market with fake orders to trick other traders into buying or selling. That makes a network appear more active, so it would be listed higher on ranking sites such as CoinMarketCap.com.

"Many of the ’indicators’ of successful chains are constantly growth-hacked," Lex Sokolin, global director of fintech strategy at Autonomous, said in an email.

Economic Value

While there’s disagreement over what constitutes an economic transaction -- Ethereum co-founder Anthony Di Iorio, said he believes that disbursements from mining pools should be considered -- most people agree that many blockchains are clogged with spam. Partly, that’s because fees to send a transaction over the network are low, Di Iorio said in a phone interview.

"If incentive structures are too low, and people are going to see more value to game the system, they are going to do it," Di Iorio said.

Elementus pulls data from blockchains and layers on information about the identities, which it deduces by using artificial intelligence and additional data, such as crawling the Internet. Pass-through transactions -- essentially, those involved in housekeeping tasks at exchanges -- account for another 7 percent of transactions on Ethereum, Galka said.

After stripping out non-economic transactions, both Bitcoin and Ethereum appear a lot smaller than currently thought, based on reports from blockchain explorers and coin exchanges. Carter figures that the true economic transaction volume for Bitcoin is about $2 billion a day, and it’s $700 million for Ethereum -- about half the listed daily volume. Assuming Bitcoin daily volume of $2.3 billion, Morris said he believes that Bitcoin is currently trading within 10 percent of its fair price.

"It’s about right," he said.