J2O stores your email addresses in case you need to fill out the Forgot Password form. And often uploads are reviewed months or years after they first get added to J2O, and maybe people shouldn't have to keep checking every one of their uploads (or the latest reviews page) every few days for the rest of their life. For example, sonicnathan1 uploaded an entire Single Player episode a few months ago, and has kept visiting J2O ever since, presumably waiting for someone else to review it.

Would it be a good idea for J2O to automatically send you an email whenever somebody reviews one of your uploads?

I'm imagining this as an opt-out setting, not opt-in, because people who are likely to visit their J2O user settings are likely to see their reviews anyway, whereas Kejero (for example) is not going to come visit J2O unless he gets an email saying somebody reviewed something.

Would this be helpful and make people happy to see that other people are still reviewing their old work? Would it be annoying? Would it be a violation of some european law I'm not familiar with?

I think this would be a very good idea.

Sounds good

Strongly agree.

Good idea, I think.