If you think what I'm saying is 'ridiculous' Moaney, just ignore me.
OP, I assumed you were using a bit of hyperbole when you said your son was 'addicted to Twitter'. Teenagers are notoriously obsessive - they go through intense and sometimes quite long-lasting 'fads' - whether that's Minecraft, Dungeons and Dragons, football, Justin Beiber, a new girl/boy friend, or Twitter. 99.9% of the time, these obsessions pass naturally. Similarly, a large proportion of teenagers avoid homework and exercise ... It is perfectly possible that your son would be avoiding these even without Twitter.
If his 'Twitter addiction' is within normal teenage limits, then my view is that taking away something he enjoys is unlikely to make him happy or co-operative. IME, negotiation and compromise work much better than bans and crack-downs.
Bear in mind, too, that you want him to manage his own online time. He won't learn self control if you take control. It's better, really, to support him to work out how he can limit himself.
If I have misunderstood, and you mean that you think your son literally has an addiction, then I'd say you need professional advice. There is a lot of controversy about whether internet addiction actually exists, and many experts believe it doesn't in its own right, but rather is a symptom of more serious conditions like depression or OCD. Techniques like CBT can help, but he'd need proper assessment. A CAMHS professional (or similar) could also advise you whether total withdrawal is a good idea, or whether some other approach is better. Most therapies are built around giving more control to individuals, not less; so again, if you think your son has a real mental health problem, then I'd say taking his phone away from him is probably a bad idea.
I truly hope your ultralaidback stance (which I have to say goes against every expert opinion I have read) doesn't backfire on you Flow4. I have a relative who was just like you and was then horrified to discover her very intelligent preteen had quite a serious pornography addiction. Needless to say, she has since tightened the rules and increased supervision.
Noone is denying the importance of social contact. However, the OP described her son as addicted to Twitter to the extent that he is not doing his schoolwork. I think any involved parent would recognise that requires action. Labelling that action as draconian, unnecessary and unkind is ridiculous.
I spend far too much time myself here and on other social media to be too critical...
Also, my opinion has definitely been shaped by the fact that DS2 learned to read directly because of a 'junior social media' - Club Penguin. Nothing up until that point had motivated him to want to work out what all those silly squiggles meant; but meeting friends online and doing the CP 'missions' suddenly made the effort worthwhile. Since then, he has had a string of obsessions with creative and more-or-less educational online/PC games like Spore, Algadoo, Minecraft and (most recently) Four Pics One Word, all of which have exercised his brain, helped him learn things, used his imagination, and increased his vocabulary.
I also think there's a common mis-perception that social media and online gaming replace face-to-face social contact. IMO that isn't the case: social media are replacing all those hours teenagers used to spend sitting alone in their bedrooms feeling lonely, bored and miserable, rather than their face-to-face social time. Young teens are especially 'heavy users', and that's because they are not allowed out as much as their older peers. IME, as soon as they get old enough to be allowed out in the evenings, they cut down their online time. My DS1 for instance (who is now almost 18) now spends very little time on FB, and a couple of hours most days (and more in the holidays) just 'hanging out' with friends.
I do take your point - and agree - that Twitter is more inane than most online activities. But it's just a medium, and its appeal will be temporary. It's quite likely that part of its appeal to WillI's DS is that it is disapproved of. Banning it is likely to make it more attractive, I'd say. I spent a lot of time as a teenager on the phone too, and trying to sneak secret phone calls when I'd been told I had to get off the phone, because talking to friends and boyfriends felt more important than anything else...
I'm not advocating limitless online time... But I do think we forget how important social contact is to teens... And I think draconian responses that say "Take away their phones!", "Ban them!", etc. are unnecessary as well as unkind.
The problem is when the internet use interferes with the rest of his life, which is what the OP is describing. I also spent a lot of time reading as a teenager, but I put the books down for long enough to study for my exams, socialise with my friends, sing with a couple of choirs etc. Some balance is needed.
I really struggle to understand why people hate their children being on the internet so much... When I was 10-15 I spent a minimum of 4 hours per day reading. A minimum. Luckily for me, no-one ever suggested confiscating my books. AFAIS, it's a different medium, but exactly the same phenomenon.
And our kids will grow up with social networks we'd never have dreamed of... Need a plumber? Ah, Jo Bloggs is my FB friend. Power cut? Don't worry, the power company Tweeted it'll be back on by 6pm and meanwhile Ali has some spare candles. Got the baby blues? 20 of my friends have had a baby too in the past year, and they're all on MumsNet, so I'm not alone...
Can you set his account so he can only access Wi-fi at home (eg phone internet coverage not covered by his tariff) and then his access to the wi-fi for only limited hours? This is what we have done with DS1. He can only access the internet on his phone at friends' houses (if he knows the password) in public places with free wi-fi, or at home between 7am and 9pm. He hasn't yet abused the privilege, but I wouldn't hesitate to block his access to our home wi-fi if he became unable to moderate himself.
My son is addicted to it...seriously. He has an iphone 5 and it rarely leaves his person. He does nothing else..no sport..no schoolwork..but does socialise by mixing with others who 'tweet'. The chat is inane too..so nothing with substance.
His life is controlled by his phone. Question...would you confiscate the phone?