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.
Metonymy is the use of a name (usually something specific like a building, or a part) to stand for something else (usually more general, like a government or organisation, or the whole thing), not the use of one example website with lots of others implied (I don't see where they are implied anyway, this is quite explicitly listing having a wikipedia account as an attribute of a good programmer - what a curious idea).
Most of the symptoms are just trivia entirely unrelated to whether someone might be talented at programming like owning a certain brand of toys, and this undermines anything serious the writer might want to say.
I misremembered, but I can't seem to recall the name of the device where you show a specific example from a class to stand in for the whole class. This is remarkably hard to search for. Please be useful and remind me what the proper name of the device is.
I think everybody is taking this article both too seriously and too literally. Sadly there is no known cure.
Signs that you have a general pattern of curiosity and playfulness could also likely include a molecular biologist with a picture of Lil Jon on her wall.
Following a general pattern is still a pattern. Patterns aren't as interesting as anti-patterns.
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.