<p>It is reasonable solution. The main problem is not in the size of blockcain itself. The problem is in growing the number of unspent outputs. OP_RETURN outputs do not increase size of Utxo database</p>

CC BY-SA 3.0
2014-08-31T16:26:24.317Z
Why is "growing the number of unspent outputs" a "problem"?
tim peterson
CC BY-SA 3.0
2014-08-31T19:03:52.097Z
@tim peterson: Client software needs to keep track of unspent outputs to be able to verify future transactions, so unspent transactions require storage space.  It does not need to keep track of transactions that have already been spent; once it has used them to verify the following transactions, they could be discarded (though some clients like Bitcoin Core keep them around anyway).
Nate Eldredge
CC BY-SA 3.0
2014-08-31T15:52:35.300Z
2014-08-31T15:52:35.300Z
amaclin
<p>I don't think so, because the use case of, "I need to pay (the equivalent of) five dollars to buy this comedian's work is more common than the use case of "I need to store this 128-bit string for an indefinite period of time." </p>

<p>Prediction: By the end of 2016, transactions intended to hold metadata instead of actually sending coins will make up less than 10% of the blockchain's size.</p>

CC BY-SA 3.0
2014-08-31T15:26:04.397Z
What will the % be in 2030? Right now in 2014 the % has to be way less than 1%, so anything even close to 10% would indicate a huge increase.
tim peterson
CC BY-SA 3.0
2014-08-31T15:19:50.937Z
2014-08-31T15:19:50.937Z
Nick ODell
<p>This is a subjective question of course, but you could view it simply as a technology finding its most compelling applications.</p>

<p>Eventually we will reach a time when transactions have to constantly complete for confirmation via the size of the miner fees that they attach.</p>

<p>When that happens, if people are willing to pay higher fees to embed metadata than to send bitcoins, then this will be the dominant use of the blockchain. If not, then not.</p>

<p>At <a href="http://coinsecrets.org/" rel="nofollow">Coin Secrets</a>, we're currently seeing the OP_RETURN volume doubling every 10,000 blocks or so, i.e. every 70 days. We'll see if that continues.</p>

CC BY-SA 3.0
2015-07-16T07:16:37.137Z
2015-07-16T07:16:37.137Z
Gideon Greenspan
<p>I realize this question may not have an answer and therefore might not be suitable for SE, but I'm very curious about <code>OP_RETURN</code> transactions.</p>

<p><code>OP_RETURN</code> transactions appear to be the accepted mechanism for inserting metadata into the Blockchain. Considering the innumerable uses for metadata (<a href="https://bitcointalk.org/index.php?topic=708193.0" rel="nofollow">contracts</a>, <a href="https://en.bitcoin.it/wiki/Colored_Coins#Example_of_an_Open_Assets_OP_RETURN_marker_output" rel="nofollow">colored coins</a>, <a href="http://www.proofofexistence.com/about" rel="nofollow">proof of ownership</a>...), I foresee more and more non-monetary transactions filling up the Blockchain. </p>

<p>Will that be bad?</p>

<blockchain><script><contracts><colored-coins><decentralized-assets>
How many OP_RETURN transactions in the Blockchain would be too many?
tim peterson
# How many OP_RETURN transactions in the Blockchain would be too many?

(Asked by: username_0 on 2014-08-31)

I realize this question may not have an answer and therefore might not be suitable for SE, but I'm very curious about `OP_RETURN` transactions.

`OP_RETURN` transactions appear to be the accepted mechanism for inserting metadata into the Blockchain. Considering the innumerable uses for metadata ([contracts](https://bitcointalk.org/index.php?topic=708193.0), [colored coins](https://en.bitcoin.it/wiki/Colored_Coins#Example_of_an_Open_Assets_OP_RETURN_marker_output), [proof of ownership](http://www.proofofexistence.com/about)...), I foresee more and more non-monetary transactions filling up the Blockchain.

Will that be bad?

**Tags:** blockchain, script, contracts, colored-coins, decentralized-assets


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## 3 answers

### Answer by username_1 on 2014-08-31. Score: 3

It is reasonable solution. The main problem is not in the size of blockcain itself. The problem is in growing the number of unspent outputs. OP\_RETURN outputs do not increase size of Utxo database

> **Comments:**
> **username_0**: Why is "growing the number of unspent outputs" a "problem"?  
> **username_2**: @username_0: Client software needs to keep track of unspent outputs to be able to verify future transactions, so unspent transactions require storage space.  It does not need to keep track of transactions that have already been spent; once it has used them to verify the following transactions, they could be discarded (though some clients like Bitcoin Core keep them around anyway).  

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### Answer by username_3 on 2014-08-31. Score: 1

I don't think so, because the use case of, "I need to pay (the equivalent of) five dollars to buy this comedian's work is more common than the use case of "I need to store this 128-bit string for an indefinite period of time."

Prediction: By the end of 2016, transactions intended to hold metadata instead of actually sending coins will make up less than 10% of the blockchain's size.

> **Comments:**
> **username_0**: What will the % be in 2030? Right now in 2014 the % has to be way less than 1%, so anything even close to 10% would indicate a huge increase.  

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### Answer by username_4 on 2015-07-16. Score: 0

This is a subjective question of course, but you could view it simply as a technology finding its most compelling applications.

Eventually we will reach a time when transactions have to constantly complete for confirmation via the size of the miner fees that they attach.

When that happens, if people are willing to pay higher fees to embed metadata than to send bitcoins, then this will be the dominant use of the blockchain. If not, then not.

At [Coin Secrets](http://coinsecrets.org/), we're currently seeing the OP\_RETURN volume doubling every 10,000 blocks or so, i.e. every 70 days. We'll see if that continues.


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