There's a group on Facebook where 19 people have declared their love for shouting: "No! You weren't supposed to shoot me!" while playing video games. It's a wonderfully resonant phrase, neatly combining that feeling of impotent frustration with a tacit admission of failure. The equivalent online these days is shouting: "No! You weren't supposed to see it!" after posting something incriminating or embarrassing and discovering that it's being pored over by an audience of several thousand greater than you intended. I've done it myself; the feeling is similar to when you accidentally send a text message to the person the text message is about. All you can do is squeak and flap your arms. A reporter for a Michigan paper, The Grand Rapids Press, came under fire last week for writing an article quoting things people had posted on Twitter. According to the wronged parties, this was an outrageous breach of etiquette. Now, I don't know the precise figures, but the circulation of The Grand Rapids Press could undoubtedly be eclipsed on Twitter by a succession of reposts (or retweets). Usually, people love being retweeted but being quoted in a newspaper is a different matter. This might seem bizarre, but social media are full of these contradictions. We're not sure what's going on, or what we're doing.

This was highlighted in the case of Paul Chambers, who casually mentioned online that he might blow up an airport if the weather didn't clear up; the difficulty in explaining to magistrates the delicate nuances of online interaction is the main reason that the faintly preposterous case is proceeding to the High Court. That's modern communication for you. I feel sympathy for Chambers, though.

I also feel sympathy for Monica Gaudio, a food blogger who, after her work was lifted and printed by an American magazine, was brusquely told by its editor that her work was "public domain". It wasn't and it isn't.

We generally own the copyright on the things we post online, including our tweets; they're just micro-blogs, after all. There may be something about their small size and huge quantity that makes people consider them disposable, but they can have value.

A whole bunch of them told the story of the Egyptian revolution, for example. Some are lovely, self-contained epithets: in 2008 a Twitter user called jster posted this, which made me laugh: "I like my women like Equatorial Guinea: small, rich and exceedingly paranoid."

The PCC recently ruled that newspapers can publish tweets and I'm sure jster won't mind me repeating it here. But if I'd used the now-defunct service Twitshirt to have it printed on a piece of clothing, maybe he'd feel differently. As I say, it's confusing.

Writers, photographers, musicians and film-makers try desperately to control who does what with the things they produce and we could make the same effort to protect our mostly tedious online conversations. But who'd be the person with the cash, the patience and the thick skin to try and enforce the copyright of a sentence that everyone's reading and republishing? The etiquette is brow-furrowing, the legalities baffling.

But to say something on the internet and claim that you didn't intend the public to see it is, frankly, like trying to defend yourself after loudly breaking wind on a minibus.

As our laptop computers become more sleek and streamlined, the comparatively lumpen brick that sits between the power point and the machine becomes even more of an irritant. Not least because the equally sleek laptop bags never seem to have space for this inconvenient lump that has to come on the journey. But on the horizon looms an end to the oversized charging brick, thanks to a substance called gallium nitride. A company called Transphorm have secured $38m (£23.3m) in funding from various investors – including Google – to develop electronics using it as a semiconductor instead of the ubiquitous silicon. Apparently it's more efficient, doesn't overheat as much and reduces the wastage of electricity in power bricks by as much as 90 per cent.

Data centres will expend less energy, we'll save space in our luggage – it's a win-win. Gallium Nitride Valley doesn't sound as catchy, but you can't have everything.