Earned media beats paid media. Taegan Goddard at Political Wire:

What Joe Biden has executed over the last 72 hours is one of the most extraordinary comebacks ever. … Biden is crushing his rivals in states that he never visited, where he had no field offices, and where he spent next to nothing on television ads. … In contrast, Mike Bloomberg spent more than half a billion dollars and it looks like he won’t meet the 15% delegate threshold in at least a half dozen states tonight. He only won American Samoa. … The key takeaway is that — at least in a presidential campaign — earned media matters much more than television and other ads.