I was teaching a ninth-grade humanities class in a New York City public school last year when I was accepted into two M.F.A. programs for fiction writing. I was over the moon: they were each funded with a stipend, and one was a school I never would’ve thought I’d have a shot at getting into. Against all odds, my dream had come true.

I quit my job. But I also turned down the M.F.A. programs, thinking that if I really wanted to write, I should just do it. That summer I started a Tumblr called “Fairy Tales for Twenty-Somethings” and within two months it went viral. In November, I got an agent. In January, we sold a book based on the Tumblr to Penguin. And, like magic, Alice in Tumblr-Land came out earlier this month.

I’ve learned a lot in writing workshops, but I learned even more from writing a Tumblr. I’m still learning from it. Tumblr is, essentially, my M.F.A. Here’s how it has helped me grow as a writer:

1. My standards for my work became higher because I was writing for a real audience—not for my friends or family, who are biased, and not for my fellow writers, who are intelligent critics but may not necessarily represent the public. The Tumblr audience is just readers who want something to be worth their time. If I didn’t produce quality work, they wouldn’t revisit my site and they wouldn’t share it with others. End of story.

2. I became a better judge of my own work. Having a real audience taught me to cut anything that was self-indulgent, since nobody would care and it was not their job to care.

3. I stopped waiting for someone else to move my work forward. There were no instructors who might offer to show my story to their publishing contacts. It was no longer anyone else’s responsibility to promote my writing (it never had been, anyway, but I finally understood that).

4. I realized that it’s not about me, it’s about the writing. Because I was already writing stories for real people, I was reminded that writing for real people is the point of what I was doing—not getting my name in a magazine or on TV, or any other fantasy that was somehow intertwined with my self-image.

5. I opened my eyes to new possibilities. Outside of the classroom, I began to see and value writing opportunities that I once deemed beneath my literary aspirations. An illustrated collection of satirical fairy tales is quite different from what is traditionally discussed in writing workshops. Releasing myself from any implicit restrictions on what is or is not an appropriate story or storytelling method was a boon to my writing.

6. I developed better work habits. Now that I’d taken responsibility for my own creative and professional development, I became more disciplined. It wasn’t about meeting someone else’s deadline. There was always something to do next.

7. I learned practical skills. I knew that I needed to build a more engaging, easy-to-navigate Web site, so I learned some basic Web design. I picked up some social networking skills, too, tagging posts on Tumblr, determining the best times to post on Facebook, figuring out what kinds of tweets got the most attention, etc. Are these things taboos for a writer? I learned how to make it easy for people to find and share my work.

8. Finally, I made a lot of connections with other writers, artists, agents, and editors. Some of these connections were made online, via Tumblr and social media; others were made in person, when I met people whose work I’d seen online.

The most important insight I gained by forgoing an M.F.A. program in favor of launching a Tumblr was learning that to be successful, I didn’t need a particular degree, or any specific family background or life experience. I didn’t have to apply to a writing program or have a friend who knew somebody. All I needed to do was make good content. Starting “Fairy Tales for Twenty-Somethings” helped me grow as an artist and writer and gave me the confidence to write the book. I needed to have an audience in order to learn how to write.

Tim Manley is a writer and illustrator; he created the blog “Fairy Tales for Twenty-Somethings.” His book, Alice in Tumblr-Land, was released November 5 by Penguin.