I disagree with this quite strongly. If you think that 'an email from Nan' is a 'read and reply' task, then you can turn everything you ever do into a to-do list. Buying a steak is a to-do item because you have to cook it. Discussing what someone's reading at the moment is a to-do item because you have to decide whether to buy the book they suggested. Etc, etc. Almost everything we do either completes a task or creates a new one, if you want to see it that way.
For extremely busy people, everything becomes a to-do list. And this is why I'm somewhat unconvinced by PG's notions of email as to-do list. It probably is if you're a busy and successful person who gets a lot of business information and requests via email.
To my mind, the reason email seems that way more than other communications is largely because email clients give you pretty good ways of turning those communications directly into to-do items (unlike, say, the telephone, where you have to explicitly consider and organise the tasks that come from those communications).
For extremely busy people, everything becomes a to-do list. And this is why I'm somewhat unconvinced by PG's notions of email as to-do list. It probably is if you're a busy and successful person who gets a lot of business information and requests via email.
To my mind, the reason email seems that way more than other communications is largely because email clients give you pretty good ways of turning those communications directly into to-do items (unlike, say, the telephone, where you have to explicitly consider and organise the tasks that come from those communications).