Even in non-fiction, beginning authors are often given the advice 'put more of yourself in it.' The idea is to move from a vanilla, pure listing of facts, to something that benefits from the writer's experience. This doesn't mean objectivity goes out of the window, just that the person's enthusiasm and interest comes through in the writing.
When we get to blogs, Twitter and Facebook, we're talking a very different kind of non-fiction. It's easy to think that it's all about opening up and letting rip. But I'd suggest good bloggers and even good Twitterers/Facebookisti, have more in common with a non-fiction writer than with someone writing in a diary.
There are two reasons for this. One is the interest factor. If your blotwfac (blog/twitter/facebook - I can't be bothered to write it all out) is only about popping down the shops, the dream you had last night and your holiday, then your readers will soon only be friends and relations. Make that close friends and relations. Just like an author, the writer of a blotwfac has an obligation to his or her audience.
I don't mean by this that every bleat (blog post/tweet) has to be a literary work of art, or that it shouldn't be about you and your life. Just that the majority of them should contain something that perks the interest. Take a Facebook comment from a friend recently. why am i hollding wine i think am drunk - on the face of it just a social comment, but done in such a way that it catches the interest and raises a smile.
The other reason for thinking more about the writing in blotwfac is that I do believe we need to remember that we are broadcasting (well, narrowcasting) to the world. And maybe there are some personal things that shouldn't be echoing around the interweb. Another friend recently had to dismantle a fair amount of her blog because of the job she's applying for. It was a good blog, but she feels rightly or wrongly that her prospective employers wouldn't like it. It gave too much of the personal away. (And with web facilities like the Way Back machine and Google cache, which keep copies of websites at different stages in time, it can be quite difficult to cover your traces electronically.)
So, yes, do put yourself into your blotwfac (that's sounds worryingly Welsh)... but do it with a little thought for what the neighbours might say.