Here's an experiment you can do at home: for just one day, keep track of how many email messages, blog posts, tweets, and Yammer  updates reach your eyeballs, your brains, and your fingers, i.e., how many are presented to you, how many you actually pay attention to, and how many you act on (if only to save for later). Here's my data from last Wednesday:
I admit my metrics are a imprecise—I didn't use eyetracking to determine how many tweets I actually paid attention to, for example—but the numbers are still sobering.
 Mozilla uses Yammer internally instead of Facebook. I haven't logged into the latter in almost two years.