Need help understanding this problem

[Dragonfall]

Under "unsolved problems in combinatorics" is this problem:

Finding a formula for the probability that two elements chosen at random generate the symmetric group Sn

Can someone explain that to me? Elements of what?

 

[JSuarez]

The elements are permutations of n objects. The problem is, given two randomly chosen of these permutations (there are n! of them), what is the probability that they generate the full symmetric group Sn.