What, exactly, is a news nugget, and what's in it?
Dave Winer suggests a nugget-of-news is 185 characters, on average. I was skeptical: He came to this number by taking the average New York Times Headline + Summary Description. That's not a news nugget: That's a news pointer.
In programming, a pointer is a reference that tells you where to look for the data, and what kind of data to expect. Kind of like the shortcuts you have on your desktop: They're not the actual documents, web pages or applications you use, but they tell you what you're going to get and take you to it.
Headlines and descriptions aren't the news: They tell you what the news will be, but the news itself is the facts, quotations and new information that make up the article. And while you'll see a lot of headline pointers being passed around on Twitter, any "social media expert" who salivates over Bit.ly statistics will tell you that including these facts, rather than just the headline, will boost interest.