Think of it this way...
Remember the old party line phone system?
Let's pretend all of our phones are connected, and Miss Nosy Body is sitting in the middle of them, listening to everything being said by everyone. You tell her what topic you want to know about - let's say Mrs. White and her husband fighting - and she taps you in, 'live,' so you can get the most recent update on their latest quarrel. You are in-the-know, immediately. At the same time, she is feeding you everything that is being said about you.... all because you are a member of her information gathering position. Technorati, Diggs and the other feeds are Miss Nosy Body.