These are just rhetorical devices. An active Wikipedia account is just standing in for active participation in sharing knowledge online. S.O. obviously counts, and MDN probably does too (I know nothing about it).

Arduino is standing in for, knowledge of things that aren't directly applicable day-to-day. Hobbyist stuff.

I think it's acceptable to define a good programmer in terms of qualities that aren't beneficial to business. In the real world this is one reason why we have and need management. A big part of management's job is to convey to the rest of staff what the business goals are and how they are to be achieved. It would be nice if all programmers synthesized this without having to be told, but I don't see why that should be considered a necessary prerequisite for being a good programmer.

ThinkGeek toys, obscure stuff are just specific examples of a general pattern of curiosity and playfulness.