When democrats fought for free speech, they envisaged the freedom for a person to say publicly what they think without having recourse to anonymity out of fear of persecution (Editorial, 19 March).

The Guardian requires a name, address and phone number for all of its letter-writers, even though it doesn’t always publish them to preserve privacy. Once the democratic world had found the optimum solution, social media reintroduced anonymity and pseudonyms as general practice, with problematic results.

The fightback could start by abolishing anonymity again, so that all internet individual or group contributions cannot be published under pseudonyms, nor without the online publisher knowing the writer’s full identity – following the Guardian’s good practice?

Dr Monica Threlfall

Senior research fellow, Global Policy Institute, London

• I’m having difficulty reconciling these two statements: “Theresa May wants to deploy an army of computerised ‘mind-readers’ to help her win the next Election, sources claim. Tory chiefs have been in talks with Cambridge Analytica … A party insider said: ‘The Tories have been in talks with these guys for about three months now and I understand they’re close to a deal’” (Mail Online, 18 December 2016).

“The secretary of state for digital, culture, media and sport, Matt Hancock, warned of an end to the ‘wild west’ of technology firms. May’s spokesman said: ‘The allegations are clearly very concerning. It’s essential people can have confidence that their personal data can be protected and used in an appropriate way’” (The Guardian, 20 March 2018).

Which of Cambridge Analytica or the Tory party should have the longer spoon?

Nigel Gann

Lichfield, Staffordshire

• I couldn’t help noticing that Alexander Nix, the head of Cambridge Analytica who (unwittingly) spilled the beans to Channel 4 about his company’s methods, is an old Etonian. Just like Boris Johnson. I don’t know what they teach at Eton but I’m so glad my kids didn’t go there.

Michael Rundell

Canterbury, Kent

• Given the Guardian’s revelations about how Cambridge Analytica really did influence the Brexit referendum and the Trump election, I suggest that Britain expels 46 British diplomats and the US slaps a large import duty on any ideas emanating from Cambridge University.

Martin Davidson

Cádiar, Granada, Spain

• One answer to the problem of Facebook (Why the ‘likes’ are drying up for Facebook, 19 March) is straightforward. Don’t use it. Now that Brexit is a little passé, being a Facebook non-user (FN) could compete with single-use plastic for becoming the most talked about subject at dinner parties, and even become quite cool.

Patrick Cosgrove

Chapel Lawn, Shropshire

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