>If I do GPL, I have to make sure that I'm following the rules set out in that license

If its all your own stuff you don't really have to care about the license. Otherwise the rules are pretty simple, include a GPL license and if requested by a user supply the source code (which you can even charge some money for).

>and making sure others who have based their code on my project have done the same.

If you don't care what others do with it, you don't have to enforce it.

As the sole copyright holder (A)GPL only gives you more options.

> and making sure others who have based their code on my project have done the same.

I do not believe the GPL requires that you make sure others who fork your code follow the GPL's rules.

It places restrictions on those others, but does not require you verify that those others follow the restrictions.

Then what's the practical difference between that and MIT/BSD licensing?

There's no difference for you. It's your code. Choosing a particular license can't restrict how you yourself use it. An absurdly common business model is for you to relicense to BSD/MIT/proprietary for a particular customer who pays you to; it's the same code, you're just not obligating that customer to share their changes if they redistribute it.

The GPL is a statement you're making about the rights that other people are granted when it comes to your code. It's not a personal pledge. Exactly like every other license btw; they aren't oaths. You're also not required to police or sue people who break your license. It's your code.

> Then what's the practical difference between that and MIT/BSD licensing?

Very simplified differences:

GPL: you shared the code with others, those others, if they modify your code, must continue to share their changes with others

MIT: you shared the code with others, those others can do as they please, including not sharing any changes they make to the code with anyone

Obviously, GPL allows you (and others) to request source code when Google uses a modified version of your code to make millions.

It doesn't force you to go after them.

With MIT, you Google would have no obligation at all to provide anything.

> It doesn't force you to go after them.

That's just it, though. If it doesn't carry any sort of possibility of being enforced, well... why bother? I could just go with the easier-to-understand license, like someone upthread mentioned.

If we're going to see the promised tech ecosystem that GPL's authors aimed to provide, we're going to need more people to take it seriously. Most people don't want to take it seriously, and if that's the case, we're better off if they just went with MIT/BSD.