It seems to me that this is native advertising as it should...

It seems to me that this is native advertising as it should be. … The content is genuinely fun, just as it is fleeting and unobtrusive. … These are the sorts of native ad projects that help change some of the traditional polarity of the advertising and publishing relationship. This is where we really see marketers challenged by publishers on behalf of users to make their advertising more fun and engaging on the consumer’s terms.

— MediaPost: Tumblr Brings Its Native Ad Format To Mobile (via david)

The benefit of running a platform with a distinct tone and hand-picking your advertisers is that people actually like the ads.