Sometimes it is the only way to get an important fact out - and I stress fact. But the greatest abuse of all is to allow sniping from the shadows, expressions of opinion or argument for policy or attacks on others from people hiding in the darkness of press-granted anonymity. We've put down rules within the AP on this and they help most of the time. That the material be both of major importance in itself and vital to the story. That all other means to get information on the record have been exhausted.
Some organizations go further.
Some just say they will never use an anonymous source. We haven't found that possible. But we have found it possible to restrict the use of anonymity, to ban it for the expression of opinion or attack. Negative news This is not a new problem. The fact is that an essential element of most news is that what happened deviated from the norm.