I had not noticed until you mentioned it, but I'm seeing the same:  my unconfirmed rewards in the Statistics page currently total 0.00257088, while the unconfirmed reward in My Account shows 0.00444093, so nothing has been added since 21304 (277495) as you say.

“Mr Bond, they have a saying in Chicago: 'Once is happenstance. Twice is coincidence. The third time it's enemy action'.”

You haven't got confirmed BTC from it.  It will be deducted from the total as soon as it is flagged as Invalid.

Rather galling, considering that our result was timed first (by one second).

It would have to be a big discount; the exchange rate is at present more than four times what it was when the Trezor was first advertised, making it a very expensive gadget indeed.  I would be surprised if anybody would wish to buy, however good it is.

I think we are simply interpreting the question in different ways.  There is a target for the number of share submissions - around 20 per minute - but not for the actual number of resulting shares, i.e. submissions x difficulty, which is how I understood the question.

From the FAQ: "...each miner is led to send results of its work to the server around 20 times per minute. That's the goal. If the miner is too fast, Vardiff increases the difficulty for its work and when too slow, the difficulty decreases."  So, no share rate target - that depends on the speed of your miners - but a target for the number of connections to the server, preventing overloading and incidentally protecting your own bandwidth.

The round is the time it takes somebody in the pool to solve a block, not for the block itself to be mined.  During this time, many other blocks may have been solved by other pools or individual miners.  If you look at the statistics page you will see the round number in the first column - these are consecutive, and relate only to Slush's pool.  Further across is the block number.  Compare this to the previous entry, and you will see that the number has probably increased by more than one.  This is because the intermediate blocks went elsewhere.

Okay, specific recent example:

21138    2013-12-12 12:17:43    0:10:04    66923249    1134    0.00041559    274494    25.05831750    94 confirmations left
21137    2013-12-12 12:07:39    0:35:35    237881115    4273    0.00047107    274491    25.11792581    91 confirmations left

Round 21138 took Slush's pool 10'04" to complete since round 21137, which solved block number 274491, so the two intermediate blocks - 274492 and 274493 - were mined by somebody else.  We solved 274494 at 12:17:43, the block itself having taken just under eight minutes from when the previous block (274493) was solved at 12:09:58 elsewhere.

Rounds therefore do not equate to blocks, except when our pool happens to solve consecutive blocks in quick succession.

I assume you are referring to the round lengths, rather than blocks?  (They aren't the same thing).  Don't worry about that.  Don't worry about the 1-day luck figure - that fluctuates wildly and means little.  Just look at the 7- or 30-day luck, and start to worry only if they vary much from 100%.  As of a minute ago they were 105% and 99% respectively, which tells me everything is fine.  Over the longer periods, short and long rounds tend to balance out.

Is there any reason why you should not do this for him?  ISTM that it would be better for one to do it than for numerous members to contact Admin.

I note that theymos is active and has logged in this afternoon.

Your miner is not sent shares of any difficulty - in fact, it is not sent shares at all.  It is allocated new work every so often, and told by the pool what difficulty of result is acceptable.  When it calculates a result whose difficulty matches or exceeds that threshold, then the result is sent, and you are credited with a number of shares equal to the threshold difficulty.

Let's say you are mining with a GPU producing on average four results per minute.  Some of those will probably be rated diff 1.  Slush has set your threshold to 1 (as it's so slow) so each of those results is accepted and earns one share.  If you were able to set your own threshold, as used to be the case, any results below the threshold you set would not be sent and thus ignored.  You might then go a minute or more and earn nothing, even missing out completely on some very short rounds where you might otherwise have had at least one or two shares.

You now upgrade to a faster miner, producing around 150 results per minute.  Slush will quickly adjust your difficulty threshold higher, aiming to receive around 20 results per minute.  Let's say it's raised to 4 - then your miner will only send results with a diff of 4 or more, and you will be credited with 4 shares per result.  Higher, but fewer of them.

In all cases the work allocated is the same: it's just the difficulty of the accepted results that varies.

The whole point of this being done automatically is that it optimises the rate at which your results are sent, preventing the server being stressed by excessive traffic, and using less of your internet connection bandwidth, while maintaining your share generation rate.  This latter can be important, for at busy times your connection speed may vary widely, and you might find that your hash rate slows down noticeably; reducing the traffic sent may limit the damage.

You can't.  The pool sets it dynamically based on your recent throughput.  As I understand it, the goal is for each worker to have around 20 transactions per minute (preventing server overload and saving your internet bandwidth), and the difficulty - from a starting point of 3 - is adjusted up or down every few minutes to achieve this.

Another member - Sunriselad - beat you to it and created a utility to do most of this.  It's called Mine Minder, and includes the block values, pool hash rate, and current difficulty.  It also displays a current bitcoin value, but I do not know what the source is.  It does not include the Slush round number.  Apparently there is some difficulty in getting the individual shares per round into the feed.

I have my copy set to download every 300 seconds (5 minutes); I believe the default is much lower, which would seem to impose an unnecessary burden on the servers.

You should be able to find the relevant post on the forum.

[Edit] try post #8211 on page 411.  Discussion follows, and there is a later version than the one mentioned.

I wonder how many miners who hop to a pool which has just had a good run of luck will also go out and buy a lottery ticket using last week's winning numbers?

I hate being a "me too", but...

21027  2013-12-02  23:04:34  5:49:17  1993521951  42217  0.00000604  272726  25.00902152  14 confirmations left

as compared to

21013  2013-12-01  12:54:49  6:11:57  1958796234  44657  0.00054740  272483  25.12828530  confirmed

It might be that your internet bandwidth is throttling the throughput.  I recently noticed that my set-up on cable broadband slows from around 8.6GH to 2.5GH in the early evening when all the World of Warcraft players and video downloaders get busy, before creeping slowly upwards to its normal level by around midnight; I tried swapping to an ADSL broadband connection and got no more than 4.5GH even off-peak.

I use a Jalapeno and two block eruptors mining through BFGminer; the reported hash rates for all three devices vary in proportion.

Which is what many people are doing, hence the rapid rise in hashing power (quite apart from new miners joining).  It's like the Cold War arms race all over again, with both sides going for bigger and better to out-do the other.  Ultimately neither will win, having spent a fortune trying, but there will be losers.

It's also known as the Red Queen hypothesis.

Yup, that would do it.

My threshold is set to 0.1 and I received a payment this morning at 01h47 GMT - a few hours and two or three extra rounds after the threshold was crossed.

I wonder - is your threshold still set below what appears to be the new minimum of 0.05?  If so, perhaps it is being treated as zero and ignored.

Somebody else recently reported getting no shares credited in their Slush account, even though cgminer was apparently beavering away.  I had the same thing happen a few months ago: the credits suddenly stopped after four days of continuous mining with cgminer.  I switched to BFGminer and have had no issues since.  Notwithstanding the occasional pool glitches, I have had everything credited that I expected.

So I wonder just where all those missing shares were going?  Conspiracy theory, anybody?

I take it that you have not made a safe copy of your private key(s) to enable the BTC to be retrieved in the event of your phone being lost, stolen, or (as in this case) broken?