Well, my account has automatically been debited for another year's blog subscription so I'd best keep on blogging for another year.

Actually I really enjoy keeping my diary this way as I have never really resolved the question of whom I am addressing when writing a diary.

Posterity? How pretentious! I know that the diaries of the most ordinary people are potentially of great interest to historians, but writing a diary with that in mind? I think not.
As an aide memoire? Well, that's all very well, but short notes in an engagement diary would be sufficient to remind me. "Went to X with A B and C" will bring memories flooding back, but tells another reader almost nothing. Only the constancy of my friendships would get in the way of accurate memory: "Was this the occasion when A sat on an ants' nest? Or was it the time that C brought all that amazing food left over from the previous night's wine lovers annual buffet?"
For some imaginary "Dear Diary"? - a friend in whom I can confide all? No, I tried that when I was in my teens and very artificial it is too, and a few years after (though less so at so great a remove) quite dreadfully embarrassing, especially my attempts to empathise with people "What dear so-and-so must be feeling at such a time. . ." just like those frightful journalists who ask questions like "How did you feel when you learned that your son had been murdered?" Well, how the hell do you think they felt?!?!?

No, far better to know that it will be read, and even commented upon, by real people - close friends and strangers alike - and that if a thought is too uncharitable to risk its being read by the subject, it is too uncharitable to write or even think. And if a thought is twee enough to be embarrassing then it should never be committed to paper (or screen). So I still don't know why I'm doing this, only that the compulsion to write things down has been strong all my life.