Look closely at the screenshot of the Harvard Business Review’s home page, above. The [rightmost article](http://blogs.harvardbusiness.org/cs/2009/09/a_single_question_haunts_me.html?cm_re=homepage-061609-_-secondary-1-_-headline) discusses the disadvantages of using of Twitter, but just below it is a button for subscribing to HBR’s Twitter feed.
OK, it’s not as straightforward as that but I couldn’t resist showing the irony lurking on the surface. The author of the article feels that it’s better to send a customised email ‘forward’ rather than Tweet a link to all your followers. I agree that if possible, one should send personal emails to show that you care for other people’s interests.
However, it isn’t possible to do that all the time, and sometimes Twitter and Facebook are simply more effective ways of getting more generic news snippets out to the masses. Which is exactly what HBR is doing with their Twitter feed.
Also, one can send impersonal mass emails (almost like ‘spam’), or use Twitter’s DM or @reply function to respond personally to someone. So it’s not like one medium is absolutely more personal than another. It is, ultimately, what you make of it.