Most Helpful Guy
You can redeem them for stuff.
Take a look at the list here.
You also get privileges like if you're XPER Level 7 or above, you don't see advertisments; you can also post more questions, things like that.1
Most Helpful Girl
You can redeem them in order to get certain things:
- Feature a question 750 xper
- Amazon Gift Card 7000 xper (for 20$ card)
- TGI Friday's Gift Card 3500 xper (for 10$ card)
- The awesomesauce GaG shirt 1000 xper (I mean who wouldn't want that shit?)
More details here: