I think this is the result of an A/B testing article which showed higher follow rates for "You should follow me" than "If you feel like following me" and other less imperative wordings.
Yup. So, anyone who cares more about manipulating their readers into being more likely to follow them on Twitter than about not being rude should totally do that.
(Is it really rude? I dunno; it doesn't offend me when I see it, though it does grate a little. But when someone says "X is rude" it seems pretty weird to respond by saying "There is some evidence that X achieves something the person doing it wants", as if that were actually responsive to the complaint.)
Incidentally, I can't help suspecting that with more people using the "You should ..." form, its effectiveness relative to other ways of asking to be followed might be less these days.
Maybe more like "trademarked". For me anyway, it immediately brings to mind Dustin's article on the subject rather than allowing itself to be taken at face value.
