Marketplace Offer vs Auto-offer

Hi

When setting up a new offer on the Marketplace, what is the difference between offer and auto offer?

Thanks!

Excuse my stupidity but what does that mean, exactly?

So, if I were to place an "Offer" this would be put to the marketplace for the community to search and possibly accept.

If i were to place an "Auto Offer" this would be for an agreed upon private trade with another player?

Thanks!