IBM moves from telecommuting to co-locating

This article in qz.com discusses some of the costs and benefits of telecommuting and "co-locating". Co-locating = working together in the same office building. It raises several interesting questions in my mind.

1. Do the relative costs and benefits depend on the type of work?
2. How has the development of new forms of communication and interaction affected the relative costs and benefits?
3. Where is the equilibrium wage higher, in a telecommuting job or one that requires the employee to be in an office during work hours?