For a new hire, it's more about standing out of average: github projects and all that. At that level connections are same CS grads that can't help much with landing a job. 10 years down the road it's more about connections with people from past gigs. Being a former roommate with someone in college is of no little help: unless that connection has been maintained, it's gone, and even if it's been maintained, that reference is of no help unless you worked together.