Support Markdown in text cells
Notebooks like https://tonicdev.com/tonic/welcome/ highlight the strength of having both text & code cells.
Support for basic text formatting features like ordered/unordered lists, emphasis, etc would make this advantage over, says, Gists even stronger.

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Matteo Menapace commented
+1, basic MD support would make Tonic my first choice for students tutorials!
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Daniel Taylor commented
I agree, just having support for lists and headers would be a huge improvement!
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Kevin commented
I could move all of my instruction material over from GitHub if this was implemented.
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Patrick Cauley commented
This is one of the most important features for me. I really want to use Tonic to replace my existing hap hazard note collection and research methods, and I use Markdown extensively for this.