If they buy at an exchange, they will have to pay the exchange trading fee.  To get the money to the exchange, they will have to pay some bank transfer or credit card fee.  Realistically, how much would they have to pay, in all, to use that bitcoin payment option?

Please note again, that the question is about customers who do not own the bitcoins yet.

There are recurrent claims that "bitcoin adoption is increasing", but there seems to be few if any reliable numbers suporting the claim, and a few signs that it may not be true.

* The number of stores that "accept bitcoin" through Bitpay or similar service appears to be growing; but since the lowest ("starter") level of merchant registration in Bitpay is free (with a 1% fee on each payment), that number does not imply growing number of clients, or growing volume of payments.  Moreover, it is hard to guess what percentage of the people who use Bitpay are "new adopters", or old adopters that buy more bitcoins specifically to use the service.  It may be that most Bitpay clients are old adopters who use Bitpay to spend their old coins, since that payment method does not seem to have any advantage for the other two categories.

* Bitpay declared that they processed payments totalling 100 M USD in 2013.  However it is not known how much of that is actual commercial payments (bitcoins changing owner in exchange for goods or services other than national  currencies); as opposed to coins being bought or sold for investment and speculation.

*  Blockchain traffic analysis shows subtantial transaction volume: about 100 kBTC/day = 60 M USD/day presently.  However, the evolution of these numbers since January suggests that only a small fraction of that volume is actual commercial payments, the rest being investment/speculation or coins being moved between addresses belonging to the same person.

* The number of new posts on bitcointalk.org had its peak in January 2014 and has then stagnated.  A visual scan of the recent posts page suggests that many of the new posts are now about altcoins. The number of registered members keeps increasing by 15'000 -- 20'000 per month, but there is no data on how many cease to be active.  The number of active members may well be stagnating or decreasing. The number of pages read per month keeps increasing, slowly, but that may be a consequence of the increased number of topics.  In any case, a breakdown of these numbers by geographic country or region and by topic would be necessary to interpret them.

Well, either it will "go to the Moon" (i.e. its price will get much higher than now, and keep rising at least 5-10% per year) or it will collapse to 0.  There is no viable long-term scenario between those two.  So, one's attitude towards bitcoin depends on which scenario one believes in.

The Mafia (and its other "competitors" in Italy) surely must have been using bitcoin since SilkRoad, if not earlier.

That is actually bullish, since the Mafia is said to have substantial influence in the Italian government. 

Also Bitstamp charges transaction fees, which means that arbitrage will not be profitable until there is a certain minimum difference in the prices, either way.  Therefore it tends to stay put for a while, whenever the trend reverses at the other exchanges.  Think of dragging a brick by string.

Isn't 'Forkerism' that which the Native Americans called 'speaking with a forked tongue'?

Isn't this what they call a 'Spoonerism'?

It looked like a fork in the thread to me, but maybe it looks more like a spoon?

Can you see it now?

That is a 10% difference. Is that what PayPal charges?

If they choose bitcoin, how much did the pay to get 360$ worth of bitcoin?

Oops, how can we resolve this fork now?

Could you guys stop that bickering and get back to the topic?

How exactly?  To the people watching the logs, those insider trades would be indistinguishable from normal trades.

Without the insider trades, an outsider would occasionally see a difference in price lasting long enough for him to exploit.  With insider trades, there would be fewer such opportunities; and when one appears, before the client can execute his trade there would appear another trade exploiting the difference and eliminating it.

Specifically, for example: the outsider sees that on exchange A the highest bid is 450$, on exchange B the lowest ask is 440$. He submits a buy order on B for 440$, but before it gets executed, someone else buys that offer; his own order just lands on the book, unfilled, while the lowest ask on B has jumped to 455$.  How can he tell that the buy that succeeded was insider arbitrage, rather than a normal trade at B, or A-B arbitrage by a luckier competitor?

It seems that almost all posts are missing the point of the question, and assume that the customer already has a substantial pile of bitcoins.

But the question was: if the client has no bitcoins, what is the advantage of

   have dollars in the bank --> buy bitcoins --> pay merchant with bitcoins

over

   have dollars in the bank --> pay merchant with dollars
 

With no regulations and no auditing, exchanges could make lots of money besides the fees that they charge.

For instance, by delaying the trade logs for a couple of seconds, they can intercept client trades and "steal" some of their money.  Suppose that the lowest ask is 500$/BTC and the highest bid is 480$/BTC. Supose that Alice posts a sell offer of 1 BTC at 485. One second later Bob, who still cannot see Alice's offer, posts a bid for 1 BTC at 495.  Normally Bob's bid would be filled with Alice's offer, and he would save 10$.  But the exchange operator sees the two crossed orders, and inserts between them a buy order of 1 BTC at 485 (that takes Alice's coin), and a sell offer of 1 BTC at 495 (that fills Bob's bid).  The two transactions show up in the log and everything seems normal, and both Alice and Bob are happy that their orders got filled so promptly -- but the 10$ now goes to the exchange, instead of Bob.

Similarly, if two exchanges agree to show their order books to each other, a couple of seconds before they are posted to the public, they can exploit all opportunities for arbitrage between them.  Any client who tries to do arbitrage will then find that the prices have always shifted against him between the time that he places an order and the time that it gets executed.

There must be many other tricks, even more profitable than these, that exchange operators can pull.  I suppose that zero-fee exchanges, like Huobi and OKCoin, get their revenue from such insider trading.  Iam told that such tricks are totally illegal for regulated stock and currency exchanges.

Obviously, any money that the exchanges make, from fees or otherwise, must come out of their clients' pockets.

Indeed, sorry, but how could I possibly remember whether that rule has been upheld throughout the following 200+ pages, and has not been implicitly weakened by precedents, namely blatant deviations that were tolerated by the community? 

Io vedo una caduta subita nel prezzo nelle borse Cinesi, con rucupero soltanto parziale, nel 10/Feb, quando Mark venne a pubblico per dire che i problemi di MtGOX si dovevano a un "bug nel bitcoin".  Curiosamente nelle borse fuori dala Cina questo ribasso permanente si verificò nel 07/Feb, mentre la caduta nel 10/Feb fu soltanto momentanea.

Credo che questo fu l'unico effetto significativo nel prezzo che si può assegnare charamente al fallimento di MtGOX, nella Cina o nel Occidente.  Molti episodi del collasso furono graduali, e perciò il loro effetto sarebbe comunque poco discernibile nelle carte.  Altri eventi discreti, come il bloccheggio delle ritirate e la chiusura finale, mi sembra che non  abbiano lasciato segni visibili nel prezzo; forse, o perchè erano già aspettati da tutti, o perchè importavano soltanto ai trader nel Occidente, e perciò il loro effetto sul prezzo fu cancellato per conto del arbitraggio con i mercati Cinesi, molto pìu liquidi.

Is it allowed to answer questions out of strict chronological order?

Yes, that is what would need to happen for me to admit that I was wrong.  But you are authorized to have fun as soon as you are satisfied that I have been proved wrong.  

Without wanting to trigger another 20 posts about my person, let me clarify that my skepticism is due to several reasons, including some political and economic obstacles that, in my estimation, are impassable and cannot be removed by any actions of the bitcoin community.  The estimation depends on probabilities that I assign to certain future developments and reactions, and my understanding of how the world works; opinions, yes, but opinions which I have construed over my lifetime, and will hardly be changed by a few arguments and statements here in this thread.    Obviously most people here have different estimations, and I do not hope to change their opinions either.  Time only will tell who was right.

I posted earlier a link to their FAQ where they say "no" - they will publish neither the winner(s), not the sale price(s).  The bidders who lose are only told that they lost.  You may try a FOIA request, but that information may be covered by some exception clause of FOIA, who knows.

The link to the FAQ is at the top of the USMS announcement.  The link is in black, whereas the surrounding text is in black, so that interested parties have more fun looking for it.  Good hunt!