In a "big company you've absolutely heard of" it can be very hard to claim that you are outside of your employer's market. Several such big companies define their market as "everything tech-related".

(Whether this would stand up in court is dubious, but do you also want to go up against a billion-dollar company's crack legal team in court?)

Also, I've heard the main issue isn't actually getting sued, it's that VCs or investors won't even touch you if there's the slightest hint that you might not own your code. If your side-project takes off it's nice to be able to enlist other peoples' help instead of miring yourself in legalities.

Unless you are shooting to make 100 million a year, any company I have heard of (thinking Google, Microsoft, Apple etc..) will not consider that a big enough market and you should be fine.

Agree with the VC thing, but assuming you are doing it outside of work it shouldn't be a huge problem, but check with a lawyer.

Exactly. It's best not to even mention it. Just keep it to yourself.

> Generally don't be a dick and work on your stuff while at work and you will be fine.

Why not? These large corporations would pay you $1/hour if the market conditions let them.

Because you are opening yourself to legal issues. Just because you think the system is unfair does not mean you should "be a dick".

The people in companies make the decisions and if you are good to them generally they will be good to you. Don't make bad blood by doing the wrong thing.

They promote you very slowly in big companies (years between), so really they aren't that good to you.