The whole point isn’t to *add* online writing on top of everything else you do. Nobody has time for that.
Rather, what you want to be thinking of doing is to gradually migrate to writing online *instead* of writing for those other purposes.
That doesn’t mean you become a blog writer and nothing else. Rather, what you’ll find is that writing for the website makes writing for all those other things a lot easier.
The idea is to take the stuff you do for private audiences and to present it (as much as you can) to public audiences.