I think Professor Welch gave the video this title to illustrate that while we use and need the machine, the machine cannot do everything without us. This makes it seem like the machine is us. We are the machine, or at least part of it, because we tell the machine what we want it to do.
Also, society as a whole can be seen as a machine in the sense that we have become so technology-driven. Web 2.0 gives us all these awesome tools to create, share, and view content, but the content itself cannot be created by Web 2.0--it must be by us.
Also, we are in charge of organizing data on the web, but we use Web 2.0 tools to do so, which in turn means we have to teach the machine to do what we want. In the process of doing that, the machine learns information about us that it might be able to use. The machine may be using us in the sense that it is able to gather information about us, compromising our privacy. Other issues are authorship and copyright. Until we figure out how to address these issues, to some degree the machine may be using us. That could be part of why he gave this title--if one were to ignore the slash.
