What are some (not illegal) ideas to make corporations feel the pain when they allow our data to be stolen?

Use bots to apply for the open positions to waste time. Reject them all for not enough pay.

Post public info of the CEO class

Piracy

Give fake data when using all services.

Start and join boycott groups.

Use their social media against them. Eg post their dirty laundry as a comment on their post.

Stop using as many services as possible. It might not be funny but, I mean, what if you went to a music store and bought used CDs instead of using Spotify? Do all of that you can.

Report bugs that don't actually exist. Keep reporting the same bug from different emails. Works especially well for apps.

Start Self hosting. Keeping my data at home is how I'm sticking it to the man these days.

Do not use actual names, birthdays, phone numbers, addresses, email addresses, etc. There's no reason they need to know that info and I love/hate seeing physical mail and email show up with my made up info. Doesn't work when paying for stuff though.

luigi had an idea

If anyone has one specifically for airlines, I'd love to hear it! Got plenty of time to read the comments with my cancelled flight

If a company is publicly traded, then all leaked individuals are given 50.1% controlling stock in the company, split among the victims with new stocks created for them, with unclaimed stocks held in a trust controlled by anyone that did respond to claim stocks. They can sell the stocks, or drive the company into the ground out of spite. Maybe even both.

Companies not publicly traded have 3 months to make all code used, trademarked material, and patents open source in perpetuity, and 1 year to convert their corporate structure into a non-profit.

Regardless of the size of the company, the CEO, CTO, and board must eat their weight in fried bugs. They get to pick the type of bug from a list of 5 options, and any seasoning they want. Live streams of the bug eating will be monetized and the proceeds given to orphans, under the title of "It's not a bug, its a feature."

Edit: whoops, I missed the "il" part in "not illegal". Anyway you should definitely not do the following. Allegedly doing the following would be arson, and society frowns upon such things.

Easy:

Identify company
Wait until it's a weekend night. We're not after the wage slaves after all.
Mix polystyrene and gasoline. Remember that gasoline can melt some plastics, so if using a plastic container for mixing do a test first. You do not want napalm all over the place.
Fill the gooey substance in glass bottles.
Cap the bottles. (see #7)
Drive to the company.
Open bottles and put wicks in them. (important not to do this earlier. Driving with open gasoline containers in your car will make you drowsy and is a fire hazard)
If you haven't already got gloves on, put them on and wipe down the bottles - you may have to leave some at some point.
Have accomplices trigger fire alarms all over the local fire department's district. Either automatic fire alarms will be discarded for a bit or the marshall will be tied up investigating.
Light a wick, throw the bottle at the company, try to get it to break a window.
If you're out of bottles or you see blue lights cheese it. Otherwise go back a step and repeat it.

I heard you should mix the gasoline with diesel for more mileage.
- Soap shavings

Explanation for illiterates?
- It’s an SQL injection joke.
  
  Basically, when dealing with databases, you can use SQL to search or modify the data in that database. By default, you can do this by polling the database with an SQL query. But this introduces a vulnerability called SQL injection. Basically, imagine if instead of filling in a name in the “Name” field, you filled in an SQL query. If the database admins haven’t protected themselves against it, then the database will happily run that query; You have just injected an SQL query into their database. Maybe you’re a malicious attacker, looking to get a virus onto the system, or looking to extract the data.
  
  Protecting the database from injection is done with something called sanitizing. Basically, you set up filters to disallow SQL, so it can’t touch your database. In this comic, the database admins didn’t do that, so they were unprotected.
  
  The actual SQL uses the student’s middle name to search for any tables named “Students” and permanently delete it. The joke is that when the school admin staff enters his name into their database, it will delete any tables named “Students” and wreck their database.
- https://www.explainxkcd.com/wiki/index.php/327:_Exploits_of_a_Mom
  
  SQL sanitization joke. Won't affect most databases today.

If someone stoles the data then the corp can't be trusted. Punishment: erase ALL records from ALL of their databases and forbid that corp to take data for at least one year. The time would depend on the severity of the leak. If the leak if catastrophic, 10 years minimum.

he doesn't rename low res episodes of the golden girls to "tax return[year].docx" and hide them in plain sight.

Not exactly what you're looking for, but Ad-Nauseum is a nice way to inject a ton of garbage into the data corps collect.

Use EICAR test strings as your password.

If they store your password in plain text the AV will lock the user database.

If your password gets leaked and they are using bad password security, when your password is cracked the AV will isolate the file.

Being a non-programmer I had to look up what that is
ELI5 please? I've read the other replies, but would love to understand a bit more.
- EICAR test strings are strings of text that can be used to test an antivirus. Basically, you bury the file somewhere, and see if your AV picks it up. The joke being that if they’re storing your password in plaintext (a big no-no from a security standpoint) then their AV will clamp down on the database once you create your account and the test string is embedded.
  
  It wouldn’t work in this instance, unfortunately; EICAR test strings are only meant to work when embedded in files that are shorter than 128 bytes. And every database is almost certainly larger than that.
Bold of you to assume a corporation storing passwords in plain text would be using AV
According to EICAR's specification the antivirus detects the test file only if it starts with the 68-byte test string and is not more than 128 bytes long. As a result, antiviruses are not expected to raise an alarm on some other document containing the test string.

This won't work, assuming the database file is more than 128 bytes long
- I think the important distinction would be 'file' or 'record'. Passwords aren't really a file in a database iirc and records in a database have a storage limit
Ah... "advice" consisting of "I've heard of a thing"
Whoa, I wanna try this now! Thx!
This is diabolical. I approve.

Don't use their services.

The fake name generator might be useful. There are also temporary email services for when a site account requires a confirmed email.

Sounds like it does the opposite of what OP wants:

I stopped counting after 2000+ vendors
Nice

If you send back one of those reply mail envelopes it costs them money. Stuff those envelopes with junk and send them back.

I don't get many of them anymore, but when I do, I mail them back with a little slip of paper inside that says "poop".
- This brings me so much joy.
But not a brick. They are apparently onto that.
- First class letter mail is up to 3.5 oz and within a certain l thickness. Every ounce costs extra over the first oz (idk about commercial return mail pricing) just stuff it with flat cardboard from cereal boxes or fill out the information wrong and put in a competitors corporate address.
- I tried the brick once long ago. 1) No way to verif it works (not just PO's the P.O. 2) That kind of shit may be why so many public POBoxes have been removed. 3) The was of paper (up to 3.5 oz?) -seems- to have worked.

Make your data useless or wrong.

More passively, there's probably an oddly large amount of John Does born on January 1, 2000 ;)

More offensively, anti-image-gen data poisoning such as Nightshade exists. It's well-defended against IIRC so hopefully someone can Cunningham's Law correct me. And this is also more solo of a movement (as opposed to gaining mass support for something)

As others have said, the best instances of direct action are illegal.

Send a copy of the receipt for your donation to the open source project that most closely aims to be their alternative. Explain why you're angry in 3 sentences and do so like you are condescendingly speaking to a five year old.

Make the letter public, so other people know & get informed.
Make the letter public, so other people know & get informed.

I'm skeptical that anything legal will work for very long because they will quickly work to make said legal action illegal.

But we can have some fun along the way, and it does change behaviour for a bit.

Use AI to generate false info to feed into their database

Maybe pirate your media and donate the money to open source alternatives

I donate all the money I save pirating to the charity of Me

I think the most effective method is to do some sort of organized boycott. We all know well enough how sheisty these companies are. Time to start encouraging each other to quit them en masse.

To bad that most participants give in and return shortly after leaving.
- me explaining how evil Nestle is every time a family member buys a product, them agreeing that's the most evil thing they've ever heard, and then doing it all over again next week ...

Sign someone up for Scientology

What we're talking about can easily be devalued, among other things.