Earlier this week, Tumblr founder, CEO, and Vespa rider David Karp announced a revised messaging service called Fan Mail to replace the site's clunky inbox service. Once activated, Fan Mail is accessible from the letter icon at the top of the Dashboard, from a dropdown menu under the user icons for the blogs you follow, and among the icons overlaid on the top right of any Tumblr blogs you visit. It's a big improvement for messaging people you follow, though the design's faux lined paper and font choices reminds us of Apple's iOS Notes app. The service will roll out to users this week; we're seeing it now on The Verge tumblr.

Speaking to Business Insider, Karp noted that a huge burst of international traffic last year shrunk US engagement to about half of Tumblr's traffic. While it's still seeing big growth, the site has yet to turn a profit, and Karp says Tumblr has been exploring app stores and a bigger marketplace for selling templates and other features as opposed to banner ads. The marketplace has had some success though, and Karp explains some theme developers have been able to quit their jobs because they're making "hundreds of thousands of dollars." Tumblr finally stabilized its notorious downtime in 2011 and rode to 14 billion pageviews in December — up nearly 500% from the year before — and there's no sign of lag in 2012 with the site ticking past a record 600 million pageviews just last week. Mobile traffic is up as well, and Karp promised updates to its mobile apps in the coming weeks.