Do I dare to write a post?

Back to blogging. Actually I've been thinking about restarting this for a while but have been dithering over theme. I don't think I can live in a glass house like Penelope Trunk , but if I wait until I have something interesting enough to share...well, my last post was three years ago. I have not been offline that whole time.

With so many publishing formats, I just haven't been able to figure out how to bring the brand together (that sounds pompous, until you consider that by brand, I don't mean just some kind of superficial persona but your points of intersection with the world.
Could we say that what separates a cheese sandwich blog from a blog about cheese sandwiches is in the first blog, the writer is the only theme and in the second, the theme is something external? Is that the key to effective blogging - something besides yourself to consistently write about?

I mean, here's the list and this is hardly exhaustive. BTW, I like table formatting and table support is a big piece of shoe in Blogger so this table will probably look bad.

Format	What readers look for	Example item
Twitter	What you're doing	I'm at a conference
Facebook	Who knows what you're doing	I went to a conference and my mom hit the like button
Pinterest	What the thing you did looks like	Here's a picture from the conference.
Metafilter	Why you did what you did	The history of this conference from the beginning of time, similar conferences, this thing that sort of inspired the conference
Reddit	Things other people are doing	What did you think of the conference?
Brand You Blog	How you did what you did	A presentation you gave, or commentary on presentation given by someone else.
Email	What you really think	I would have rather stayed home.