The short version is that Gawker Tweeted Mein Kampf.
The less short version is that Gawker "tricked" Coke's Twitter bot into retweeting their own tweets of Mein Kampf.
The slightly less short version is the above plus disturbing claims by Max Read who tries to believe that Coke has intentionnaly promoted Hitler's work:
Coca-Cola a white nationalist organization? Its Twitter says: Yes.
If anyone was intentionnaly doing anything, it was Adam Pash from Gawker. He created a Twitter account, @MeinCoke, that tweeted Adolph Hitler's Mein Kampf. His goal was to get Coke's Twitter account to retweet them, the goal either being to reach a greater audience or be able to call Coca-Cola a Nazi.
In the end, Coke deleted their automated tweets and stopped their operation. Gawker has been boasting their "white power" beliefs by publishing their Mein Kampf ASCII tweets across multiple "articles" of theirs.
In conclusion: Gawker a white nationalist organization? Its Twitter (and website) says: Yes.