What are props for?

its for something you did and they liked so they give you those as unspendable points

If you really like someone's photo, answer, pick, quiz, link etc. you give them a prop for it.

^also just to randomly give them a prop because you either like them or wanna talk to them on their blog/homepage so instead of sending them an actual message you just put it on their blog along with a prop. lol...