How do you become a co-chair of a working group like this?
The high level of interest and activity in the community led W3C to form an interest group to explore if payments was a WG-worthy topic and I also participated in that.
When we finally chartered the WG I was approached to chair and agreed. We've re-chartered twice since and I continue to chair.
The job is made a lot easier by the fact that we have a great W3C staff contact who does all the heavy lifting.