Would you like to have a service where you can get experts answers of your questions?

I would for something particular, for instance car repairs. Else, wouldn't Quora be a go to for something like this?

I'm using Growth mentor from time to time. I would say what matter for your platform to b successful is to focus on a niche. Also do you plan the answer to be open like on Quora or visible only to the one who asked?

For sure, but will this service provide answers to any kind of questions?

What would be the difference with Quora or stackoverflow?