I'm not sure about all this. I can understand why Twitter can be useful, and its a quick way of sending out information to people. Blogs are just a longer version of Twitter in my view. RSS feeds are probably useful too. As for Pushnote - I haven't even gone there as yet. I think doing them all is probably silly. Just see which one you like the best and choose that one to use. Blogging is ok, but do people really have time to read them? I suppose it depends on the nature of your work. It's nice to read the musings of people and some of them are quite entertaining but do we really need them for our work? I was dead against Twitter - in fact, I was cringing as I signed up for it, but after looking at it, I've drawn the conclusion that perhaps a few words and a link is all it needs to get the message across to people you want to send info to.
I shall have another review and perhaps look at Pushnote.... and reflect what I've seen on here... if I can be bothered ;-)