Yahoo didn’t waste any time getting more ads on Tumblr once the acquisition was announced. In May, the company started showing sponsored posts to users on their dashboards on the desktop.

Now, in December, they’re getting ready to launch their fifth ad unit – their second on mobile. Todd Wasserman at Mashable reports:

This month, Tumblr is introducing its second mobile ad unit, Sponsored Trending Blogs, which leverages one of Tumblr’s most-read sections.

Tumblr CEO David Karp once said that the idea of ads on Tumblr “turned his stomach,” but it’s Yahoo’s to do with it as it wants now, and you better believe ads are a major part of that. I doubt this will be the last unit we see.

Other units so far include Radar, Spotlight, Sponsored Radar, Sponsored Spotlight and Sponsored Mobile Posts.

The addition of ads was a major concern among users when the acquisition was first announced, as the site had historically been virtually ad free. It will be interesting to see how far Yahoo takes it, and how users respond.

Image: World Economic Forum (Flickr/Wikimedia Commons)