They cast a wide net. As far as I can tell, recruiting responds to every application with an invitation to come in for assessment. (I'd estimate they pump ~20 people through their factory farm of math-only IQ testing per day.) The facility is nice, grounds are manicured, employees are polite, etc, but one quickly realizes they're taking every advantage of the employer's market.
As a recent grad without years and years of work experience, I was relieved to see they pre-screen with an "aptitude assessment." I thought it would give me a nice advantage (I'm verbally brilliant--800 on the SAT verbal and writing portions, could write a dictionary from memory, etc) and highlight a valuable quality I can't really put on my resume. Unfortunately, as I reviewed the cheat-sheet they give you beforehand, I realized the test consists of three sections--all of which select for right-brained thinkers. Why it's more important that a customer service rep remember the substitution method of linear equations than be able to speak articulately, put people at ease in person or over the phone, and the rest is beyond me.
Really looks like it could be a great place to work, but I'm not seeing the logic behind recruiting's (management's?) initiative to hire a company full of people with identical intellectual strengths.