For instance - on writing in detail we could have key questions that pop out and say - something.

Either the notes are locked by the author if shared or others can contribute to these notes.

The evolution may be that people can give live feedback on their experience with a webpage etc -

For me i want it to remind staff and myself to address particular things when submitting a form on a website that i can not control.

It would work by having a trigger webpage - in this case https://forums.opera.com/category/25/forum-feedback

And a little pop-up could come up and show notes from the last time i used this service.

If i was shopping for flights i could put the cost and date in these notes whenever i go on that page and see how they are changing etc?

I'm sure their is far more this feature could bring and particularly the ability to share these 'Triggers with others' if they wish to add them to their browser.