Snowden released his information to journalists who carefully vetted each item for newsworthiness with the participation of the US government. Then that data was parceled out over many months, so it would remain in daily news cycles and continue to generate commentary over that time, staying in the public's mind.
Manning gave her data to Wikileaks, who posted it online in its entirety.
The Guardian ran everything by the US government first before publishing. Every responsible journalist does. They're looking for a response or comment to the story, to make sure they didn't get anything wrong, and to see if there's a any reason to withhold details (a reason beyond "It's classified so don't").
In fact, in Greenwald's book No Place to Hide, he describes how they held off publishing for several days while waiting for a response from the government. Greenwald was so frustrated with the delays that he considered quitting the Guardian and going on his own. I think that's the idea that eventually turned into The Intercept.
If that's the case, how did they get almost everything wrong? Reading the original stories on The Guardian, I couldn't find any response from the US government.
Snowden released his information to journalists who carefully vetted each item for newsworthiness with the participation of the US government. Then that data was parceled out over many months, so it would remain in daily news cycles and continue to generate commentary over that time, staying in the public's mind.
Manning gave her data to Wikileaks, who posted it online in its entirety.