Less than two weeks after Yahoo announced its acquisition of Tumblr, the micro-blogging platform is unveiling a new feature for its desktop site. Starting today, users will see sponsored content mixed in alongside posts from the blogs they follow. Previously, sponsored content from brands was only featured in Tumblr Radar, located less prominently to the right of the Dashboard. Though the goal is clearly for paid content to blend in with regular posts -- see that dollar sign above? -- we're sure Tumblr users will sniff out the difference instantly.