Tumblr allows advertising at $25K a pop

Just one month ago, Tumblr CEO David Karp announced that displaying ads was the "complete last resort" for the microblogging service. Well, financial temptation must have gotten the better of him.

Tumblr announced the introduction of Tumblr Radar and Tumblr Spotlight today, which are two types of advertising products available to sponsors for an entry-level price of $25,000, according to VentureBeat. Although this is an about-face to what Karp said last month, there are still some conditions for potential advertisers.

First, the advertisers must be "approved" by Tumblr. Second, they must be willing to shell out $25,000 (for comparison, ads on Twitter start at $15,000). And third, the ads must tap into the "visual nature" of Tumblr.

"We're looking for the world's greatest marketers and media companies to help us raise the bar for creative advertising on the web," Tumblr wrote on its sponsors page.

Once these hurdles are cleared, advertisers can pay to post content and have increased account exposure on the blogging platform. Radar displays ads on the right-hand side of users' dashboards and Spotlight features advertisers for users to follow on the site's directory pages.

Tumblr began moving into advertising territory in February when it launched "highlighted posts" allowing users to pay $1 to get their post to stand out in the Dashboard. But Radar and Spotlight is a much bigger shift into full-fledged advertising.

With nearly 55 million users, Tumblr has a massive audience. In the five years since it launched, users have posted to blogs more than 22 billion times and the company has received $125 million in funding. It also grabs 4.5 billion impressions per week.

The company will begin displaying a few advertisers ads on the site's dashboard and directory pages starting this week, according to The Wall Street Journal.

CNET contacted Tumblr for comment. We'll update the story when we get more information.