Bitfortip offers a unique use case thanks to Bitcoin.
Use Bitfortip to:

Find a item (i.e. a dress ) that you saw on a magazine,website, Pinterest or Instagram and you don't know where to buy it online. You can upload it as photo using your smartphone and ask bitfortip members to search it online for you in order to win the bitcoin reward.

When you sign up, a unique bitcoin address is generated in your account.