user1525: Currently, it is a timer which counts down from 10 minutes starting when the transaction is first seen. When the timer reaches 0 minutes, it switches to "Unknown / Never." 
It is my understanding that finding blocks (and confirming transactions) is a Poisson process, hence the correct value should be a constant "10 minutes" and then "Confirmed!"
Is my understanding wrong?

user659: The expected confirmation time should really take the priority of the transaction into account.  If a transaction has insufficient fees attached to it then it will tend to take longer to confirm.
I don't know if blockchain.info takes this into account or not.

user516: You're correct; the expected confirmation time from any given point in time is always around 10 minutes (it may be a little more or less when the network hash rate has changed since the last difficulty adjustment). This question looked at that exact issue.
Note that a retailer (or other transaction acceptor) doesn't necessarily need to wait for a block to be solved in order to accept a payment though. More info here:

How has the problem of waiting for confirmations been eradicated?
How do I safely accept bitcoins without waiting for confirmations?


1525: <p>Currently, it is a timer which counts down from 10 minutes starting when the transaction is first seen. When the timer reaches 0 minutes, it switches to "Unknown / Never." </p>

<p>It is my understanding that finding blocks (and confirming transactions) is a Poisson process, hence the correct value should be a constant "10 minutes" and then "Confirmed!"</p>

<p>Is my understanding wrong?</p>
 659: <p>The expected confirmation time should really take the priority of the transaction into account.  If a transaction has insufficient fees attached to it then it will tend to take longer to confirm.</p>

<p>I don't know if blockchain.info takes this into account or not.</p>
 516: <p>You're correct; the expected confirmation time from any given point in time is always around 10 minutes (it may be a little more or less when the network hash rate has changed since the last difficulty adjustment). <a href="https://bitcoin.stackexchange.com/q/3909/516">This question</a> looked at that exact issue.</p>

<p>Note that a retailer (or other transaction acceptor) doesn't necessarily need to wait for a block to be solved in order to accept a payment though. More info here:</p>

<ul>
<li><a href="https://bitcoin.stackexchange.com/q/3240/516">How has the problem of waiting for confirmations been eradicated?</a></li>
<li><a href="https://bitcoin.stackexchange.com/q/328/516">How do I safely accept bitcoins without waiting for confirmations?</a></li>
</ul>
