All you need to do is solve an open-ended predictive modelling problem.
The social network recently posted this data science competition on Australian start-up Kaggle.com:
The challenge is to recommend missing links in a social network. Participants will be presented with an external anonymized, directed social graph (no, not Facebook, keep guessing) from which some edges have been deleted, and asked to make ranked predictions for each user in the test set of which other users they would want to follow.
No big deal right!?