What does it mean when a woman gives you a thumbs up?

[LinkxPeach]

Earlier at Jewel-Osco today, I was asking a woman, “to get a change for a dollar”. Then, I gave her 4 quarters and she gave me a thumbs up.

[Siren777]

As a thank you in your case. Usually to agree with someone. Or you like the topic, object or person but not necessarily in a romantic way. As a friendship.

[FilmGuy93]

She was just saying "thank you"