wholocked,
that's funny, because yesterday I discovered the shot of the security camera, too, and - yes, you are right- Andy is definitely putting the diamond into place with his left hand. And not only that: He's putting it at a different spot on the glas. Such a big continuity cluncker really annoyes me, because the leftie/rightie thing is often very important in classic mystery stories.
Anyway, since it was my big theory, that the twin theory could be proven by different handedness, I looked again at the scenes, which might indicate Moriarty's handedness in all episodes, and found many more inconsistencies, not only with the phone, but with other things, too. Even his body language is not compatible with a pure leftie.As I said before, I have done a lot of research into the handedness problem, job wise and for personal reasons. It's far too lenghthy and complicated to give a detailed analysis here. I came to the conclusion, that either they wanted to show Moriarty to be ambidextrous for some reason (maybe just to troll us, lol!), or that Andy Scott is ambidextrous or a leftie with strong ambidextrous tendencies. At the moment I'm going with the latter, because clips from Andy in other roles, and the ease of his performance seem to confirm this. I had dismissed this thought before, because it's so unlikely. While about 10 % of humanity is left handed, only a very small percentage is  crossdominant, and an even smaller percentage is ambidextrous.
While I personally still think, the twin theory has some merits (there's still the discontinuity of Moriarty's facial hair growth, which of course could be artistic licence or an error as well), and could be a compelling story line with a nod to canon, if handled skillfully, my arguments have become weaker: it cannot be proven by looking at the handedness.
This kind of continuity errors make me a little angry, because it's not even a fleeting thing, which you could only detect in super slo mo. It makes you question, how m

This is just a wild guess, but has anyone wondered, if Sherlock was speaking from his own experience, when he speculated, how the little boy, 'this particular little boy, who reads all the spy books', might react,when he sees the outline of a man with  a weapon through the glass door? I can't recall any spy books on his table, only spy toys. And if you see the ouline of a shadow through a glass door, it's quite a leap to think immediately of an abduction. Sherlock really seems to identify with the little boy. So far, there was no indication in the show, that Sherlock has special insights into kids.In the contrary, he's quite harsh with the kids in Scandal, who ask about their  dead grandfather. Also the Bluebell case in Hounds doesn't interest him because of the poor kid, who lost her pet.
Now, if something frightening like an abduction  had happened to Sherlock as a kid, Mycroft might have told Moriarty about it, amongst other things concerning Sherlock. If Moriarty had arranged the abduction in order to smear Sherlock as a fraud - and, we know, he did just that - the whole thing would gain much more punch, if Rich Brook told Kitty that fact of Sherlocks life, which could be easily verified as well, and people would read about it in the paper the very next day.

shenanigans, I wouldn't put it past Moriarty, to call a nuclear disaster part of a game, but I can't see, how 'Oxygen' fits into this scenario, but I'm no expert here. Also, if we look for an alternative meaning of IOU, I would look for something, where these letteres forms an entity as a whole, some people might recognize. As I said, if you look for IOU as something, the IT-community might know about,there is far more than the 'evilrouters' website, and it's in many languages. Also it ties neatly with 'Jim from IT' and Prof. Grimm's teachings. The question is, if something like that lends itself to crime, if used and altered by the wrong persons.
I noticed Sherlock's muttering in the lab, and interpreted it as him being in his mind palace, searching for a meaning by association. But it's interesting, that you mention this scene, because it shows , that Sherlock doesn't leave things with just 'I owe you a fall', but he is searching for alternative interpretations, just as we are.
I like your idea of Moriarty trying to cause damage from beyond the grave, and, at least concerning Sherlock and his friends, he certainly has succeeded, but maybe, there's more to come.

Irene, I'm no language expert, but my impression is, that 'I O U' and 'I owe you' sound the same in English, though Jim's pronounced emphasis on each letter 'I O U`' is interesting and made me think, that it is part of the riddle in it's double meaning.
I've the English dvd version with English subs only, but there are still mistakes. In Scandal they have 'short hair' instead of 'short hand' for example, when Sherlock analyses the jury.
How do they do the word play (IOU vs I owe you) in Spanish though?
Don't get me even started on Sherlock's German voice... I will only watch the German version on tv in May, when I can  lure in some friends into new fandom, lol!

shenanigans, wow, your find about Turing and the poisoned apple. And the show being aired in the beginning of 2012, the 'Turing Year'!
The decoders of Bletchley Park have been mentioned before in Scandal, when they alluded to the Coventry dilemma.
One more thing to Prof. Grimm: if you go through the second document, shenanigans linked for us, you find, that he apparently touches safety issues of mobile devices in his teachings. He mentions, that iphones can be tracked and thus compromise the privacy of the carrier. Now think back again to 'Study in Pink' : The cabbie can be tracked by the 'mephone', the lady in pink planted on the cabbie, as Sherlock deduces so brilliantly in my favourite scene (it's a drug's bust), but only after Anderson turned the other way, lol! Now, it's quite possible, that someone like Prof. Grimm is an advisor for a show like this. I know university teachers, who were advisors for 'Star TreK' and loved it. It's pure speculation, but contacts like that are not so strange.

Dunno about Masonic handshakes... ACD was a mason (Phoenix Lodge) , but I can't see a viable angle here. Also, the handshakes, we see here, are certainly not masonic but quite ordinary. Masonic handshakes look different.
But since we are dealing with a Sherlock for the 21rst century, I like the IT angle, Prof. Grimm from Germany might represent, especially since Moriarty was introduced to us as 'Jim from IT', before we learned, that he is the super villain of the first two seasons. If Jim worked in the IT department, he must be somewhat knowledgeable in that area.

I tried to find something about secret handshakes or signs in the canon, and couldn't find anything. However, ACD used a lot of coded signals and languages as plot devices. I found a book for kids about codes and signs, and there is a whole 'Sherlock Holmes' chapter in it.

http://www.scribd.com/doc/69771804/PR-Secret-Codes
(chapter 7 is the relevant one)
Also, Steve Thompson also wrote the much maligned 'Blind Banker', where codes and secret signs feature prominently. So, it's not out of the question.
wholocked, I feel with you! Watching RF again and again feels a bit like Ground Hog Day, lol! But like in the movie, each time I watch a scene again, it seems to be a little different and I discover something new.

And shaking hands is not something, Sherlock does out of a polite routine all the time.
Like you, when Jim grabs Sherlock's hand, I thought 'You're dead, man!'

Well, the cabbie was not a very nice man, as John has pointed out to us, so I perfectly believe, that he might have cheated.
Sherlock was right, you can manipulate as much as you want, it's still chance. And if I had been the victim of the cabbie  - even, if I would believe in his manipulative super powers - there are ways to bring it back to a 50% chance: I would just have not played the manipulation game of guessing and second guessing with him. I would have said something like 'one, two - out are you' in my head to create a 50/50 chance for myself. The cabbie could not have prevented it. So he was either 4 times lucky, which is not really that outrageously unbelievable (the sample here is not really big enough for  viable statistics), or he cheated. If he cheated, John's intervention was literally vital for Sherlock, and I guess that was the main point of that scenario. The cabbie goaded Sherlock into almost doing something unbelievably stupid, and John rightfully calls Sherlock an idiot for engaging in such risky behaviour.

i guess, I've infected some family members with the 'Sherlock Virus' after all. My son told me this weekend, that he got all his friends into the show. They are also now very excited about Ben Cumberbatch being Smaug in the upcoming 'Hobbit' movie. When I told him, that Ben not only gave Smaug his voice, but that he did also the motion captions for Smaug, he said: 'Why did they motion capture him? Cumberbatch looks so outlandish,  especially his eyes... he could portrait Smaug just with his eyes, his body and his voice and make us all believe, he's a dragon. He is just that good as an actor!'