Hmm. I think that WMF already posted about Ed's battleships if I recall
correctly. I think that's like someone posting about their favorite flower,
animal, vacation spot, economist, car brand, or television series. Just as
on Wikipedia, people tend to write about subjects that they're interested
in. If we prohibited people from writing about all of their personal
interests, then we would have a very small number of writers.
That said, what I would be thinking about are noteability and undue weight.
For example, someone tweetung daily from a WMF account about different
types of rocks would be a problem as that would likely give undue weight to
that subject.
I'm sensitive to COI as well, but it's possible to be so sensitive to it
that lots of benign activities would fall under the definition of COI.
Pine