I find #2 to be very interesting, I can also see how the action of writing can help reinforce other skills/knowledge. Therefore blogging could be a form of self

I find #2 to be very interesting, I can also see how the action of writing can help reinforce other skills/knowledge. Therefore blogging could be a form of self education or improvement. #1/#3 seem quite specific but I can see how some people may write with those in mind.