Microblogging has almost become a commodity in most (social) networks and has become a lot easier since almost each microblogging service has their own (open) API. The fact that you no longer need the interface defined by the network to microblog but you can use another third party tool (for example TweetDeck or Twhirl) of your choice to do it is an immense step forward compared to social networks four years ago. The downside of all these tools and APIs is that they can be misused for distributed microblogging.
What is wrong with distributed microblogging you might wonder. Simply it adds more noise than necessary to the already noisy microblogging environments. It adds this extra noise because all of your networks are different in a certain way. Compare it to the moments in your life that you are communicating with other people face to face. When I talk to my grandmother I talk to her about different subjects in a different manner than I would be talking to my colleagues and friends. My grandmother would even be confused if I would talk to her about the wonders of social networking or new features on Twitter.
Now lets go back to distributed microblogging: there too are the exact same situations as mentioned above. Your network on Yammer, Twitter, Facebook, Identi.ca are different networks with different people and different contexts. If you just blindly publish all your content through all the channels you create extra noise (content your connections are not always able to relate to, or in the worst case do not want to relate to). Therefore: do not push all your content to all the possible network your tool might support. Publish your content on the networks on which it adds value and do not publish it everywhere because is it so easy to do so.