I was under the impression the purpose of vice taxes is due to activities causing societal harm, not self harm.

If it was self harm, then seems like we should start with vice taxes for added sugar and not doing cardio workouts.

Sufficient self harm at scale is societal harm.

> vice taxes for added sugar

At face value, this doesn't seem like a bad idea. I've heard about cities in the US that have a tax on large sugary drinks.

> not doing cardio workouts

It's probably easier to incentivize the good behavior here than punish the absence of it.

The government giving money for doing something versus taking money for not doing something is the same thing. Both are incentives for a certain behavior.

Okay. Use of Facebook has been linked to worse mental states, and groups on there have produced negative externalites. So how about a per-byte tax on in transmissions to/from Facebook?

From the self harm angle: if you can provide meaningful evidence that use of [social media] results in negatives that far outweigh the positives in virtually every case (this is true of smoking), then this tax makes sense. This isn't easy, though, as millions of people have benefited massively from social media.

As for societal harm, I imagine going forward we'll settle on some countermeasure against entities like Facebook. If that's a per-byte transmission tax, then so be it.

Perhaps a tax that scales with the frequency that someone uses social media? If you rarely use it, the marginal tax is near zero. As your usage increases, the marginal tax applies increasing friction.

Clearly "what's bad for you" is subjective given that there was a time when many would have said that masturbation causes self-harm.

The other issue is that sin taxes just don't work. They don't stop people from partaking at all. These taxes are just a money grab.