Never underestimate how important it is to make friends with the people you work with. There are pros and cons to work friendships of course, but overall I think people like to keep their friends around at work. If someone moves on to a new position, it's natural to look to your friends to fill any new openings that come up.
That's even true in the NFL, where newly hired Rams Coach Jeff Fisher has just hired his pal Gregg Williams. I was touched by Williams' statement on his friend Fisher. He said, "I have a very close and tight circle of friends. Not many people get inside that circle" and that when Fisher called him it was a no-brainer for him to work with his old friend. He also said, "Friendships and relationships in this industry are hard to come by."
I think that's true of any industry, where more and more it seems people are opportunistic rather than genuine. It might be difficult to figure out who your friends really are, but when you do there's no doubt that it's worth it.