I think our company can create challenges designed to find software engineer candidates who are:Good at solving problems, not at wowing recruiters.More likely to be afraid to come up to us at a career fair.More likely to be underutilized in their current programming job but are too introverted to do anything about it.For an example see this article that discusses Facebook hiding an email address in an image using Piet.I just can't find any studies or hard data on whether this actually works or not.  
How effective are programming challenges in the recruiting process?
recruiting;challenge