[1] In September 2004,[2] Mann founded and began the exclusive writing for 43 Folders,[3][4] a blog about "finding the time and attention to do your best creative work.

In 2007, Mann launched You Look Nice Today, an award-winning comedy podcast that bills itself as "A Journal of Emotional Hygiene",[4] an effort he created with Adam Lisagor and Scott Simpson.

The show's run ended in 2015, but a spiritual successor called California King was created in its wake in 2020 with the same team.

[23] In June 2015, Mann began a 10 podcast series with John Siracusa in collaboration with Relay FM called Reconcilable Differences, which has since been extended.

[24] Mann has also appeared as a guest on other podcasts, including the CBC radio show–podcast Spark, The Chronicle of Higher Education's ProfHacker,[4] Scruffy Thinking, CMD+SPACE, and various episodes of Dan Benjamin's The Conversation.

On February 26, 2007, Mann launched The Merlin Show, a video podcast primarily dedicated to long-form interviews.

Mann has been described as the "inventor" of the Hipster PDA,[3] a paper-based, DIY personal organizer that uses design cues found in David Allen's Getting Things Done.