Patrick Cosgrove (Letters, 21 March) argues that the answer to the Facebook data scandal is simple – stop using Facebook. Alas, this completely misses the point. A few of us have never been a member of Facebook, but they still hold data about us, gathered from our friends and family who do have Facebook accounts. Worse, given that Facebook also buys data about people from third-party brokers, the profile they have on us is probably far more detailed and complete than we might like to think. The Facebook AI systems may know where we live, where we used to live, our work history, quite a bit about our movements, the people we know, where and how often we meet, how rich or poor we are, our interests, political outlook and so on. This is not trivial. The more they know, the more they can deduce and infer – and the more that information can be abused when it falls into the wrong hands.

It was said some years ago that the credit card companies had such good profiles of us that they could predict when a marriage was going to break up before the couple did. This may well have been apocryphal, but behavioural prediction has come a long way in the last few years. I have no doubt at all that this is now a prediction that can be made with a high degree of accuracy.

I studied cognitive science at postgraduate level 15 years ago. I took a special interest in AI, such as it was back then. The field has since changed beyond all recognition. The development curve is exponential. I suspect there are AI systems – perhaps belonging to Facebook or Google – that are performing feats that would have us all screaming for legislation if we knew about them. And if not today then certainly very soon.

Robin Prior

Tyntesfield, Somerset

• The situation is more profound than a need to change the laws that regulate the web (Editorial, 22 March). The web standards and structure have been created and moulded by corporations to suit their own purposes. As Lizzie O’Shea’s article pointed out (Time to cut ties with the digital oligarchs and rewire the web, 20 March), the rules of the internet need to be written by ordinary people, not corporations.

I regularly contributed to the World Wide Web Consortium (W3C), which sets standards for the web, and raised my concerns over approximately a decade, and their “communities” programme was one outcome. A primary difficulty is conceiving how one might engage ordinary citizens in authoring web standards; this is very dry, technical work.

Jonathan Chetwynd

London

• Alex Hern (Why have we given up our privacy so willingly?, G2, 22 March) quotes Richard Stallman as saying “I recommend a law prohibiting any system that collects data … unless [the owner] can justify it as absolutely necessary for the function to be done”.

This is precisely one of the principles behind the forthcoming EU general data protection regulation (GDPR), which comes in to force on 25 May, at least in regard to personal data. Article 5 states that personal data shall be “collected for specified, explicit and legitimate purposes and not further processed in a manner that is incompatible with those purposes”; shall be “adequate, relevant and limited to what is necessary in relation to the purposes for which they are processed” and shall be kept “for no longer than is necessary for the purposes for which the personal data are processed”. The collecting organisation is required to provide a clear privacy statement and supporting documentation to show how these principles are embodied in its data processing systems.

As someone who has been advising a number of organisations on what they must do in order to demonstrate (and not just merely claim) compliance with the GDPR, I am quite impressed by the seriousness with which the authors of the regulation have taken privacy issues. I agree that it will need to be reviewed and updated on a regular basis, but as a starting point it is really very good. I just hope the regulator (the information commissioner, in the case of the UK) is as assiduous as the regulation deserves.

John Dobson

Professor emeritus of information management, Newcastle University

• Appalling (and sleazy) as Cambridge Analytica’s behaviour is, or was, I am puzzled by the hysteria over Facebook. Not being a teenager or someone who thinks food needs to be photographed for posterity before it can be digested, I have never had a Facebook account. But even a luddite like me finds it odd that anyone using Facebook thought their data was not being harvested. Exposing the guts of your life online and expecting that a free-to-use platform is not gleaning something is like eating burgers six times a day and being surprised that you get fat or smoking and being surprised that you end up with lung cancer.

How lovely it would be if the same politicians who are on the current slam-social-media bandwagon had shifted themselves over the decades while the public was being fed bilge by the gutter press – paving the way for, among other things, Brexit.

Amanda Baker

Edinburgh

• One great advantage Ambridge Analytica (Pass notes, G2, 22 March) has over Cambridge Analytica is that it doesn’t have to rely on the doubtful truths to be found on Facebook to measure the mood of the residents of Borsetshire. It can analyse the grunts of Joe Grundy instead, a far more accurate guide.

Keith Flett

London

• Apart from promising you that I am not the water-based wing of Cambridge Analytica, I’m happy to provide the number of the nearest bridge where I’ve moored for the night in support of your efforts to ensure that the Guardian letters page remains a troll-free zone (Letters, 21 March).

Ian Grieve

Gordon Bennett, near bridge 99, Shropshire Union canal

• I’ve tried to take Alex Hern’s advice (How to quit Facebook, 20 March) but every time I try to delete my Facebook account it “times me out”, meaning it’s impossible to get out. Anyone else having this problem? Are we trapped for ever? Feels thoroughly dystopian. How to escape? Help!

Jol Miskin

Sheffield

• Surely I am not the only person to believe that if God had meant us to use Facebook, He would never have given us email?

Roger Backhouse

York

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