Very convenient! Rated 5 out of 5 stars

I like the idea and the extension's features. :D This does not only allow you to use Markdown but, as a consequence, also free-form HTML code which you can quickly turn into the "real thing" even in Gmail (which by default does NOT allow HTML). It also has the feature of customizing the CSS of the rendered markup, which is awesome if you want to give it a unique look.

This review is for a previous version of the add-on (2.9.4). 

Be alert of information loss! Rated 3 out of 5 stars

If you modify the text when you're in the converted state, and click MarkdownHere button to convert back to original text again, you will risk losing some or even all of your text!

If you enabled HTML source editor mode and click MarkdownHere button in HTML source editor window, you will risk losing all your input text.

If you save the draft message and open it again for further editing, MarkdownHere may convert the text into wrong format of quoted block, because Thunderbird will beautify the HTML code with indention and MarkdownHere can't handle it correctly.

Solution: The HTML text should be converted back to plain text, before formatting them with Markdown. You can do it manually by copying the text, then Ctrl+Shift+V to paste plain text, then click MarkdownHere button to format them.

There should be a transform status feedback, when switching on and off of Markdown conversion. eg, MarkdownHere button pressed down or released up.

Conversion done by MarkdownHere is NOT recorded in Thunderbird undo history, so you can NOT revert it by pressing Ctrl+Z to undo the edit! This will cause data loss if you're not cautious when using MarkdownHere.

This review is for a previous version of the add-on (2.8.1). 

Rated 5 out of 5 stars

A fantastic plugin! I'm a big fan of Markdown and find it much easier than using WYSIWYG editors. This add-on really makes writing emails a lot easier for me. It works well, and as advertised - but more than that the rendered email looks really good. Thank you for making this!

When I first installed the add-on I felt it was a bit of a shame that you need to toggle the markdown before sending. After using it, however, this didn't present an inconvenience I had anticipated.

The only minor issue is that it's not clear which 'mode' you're in. Usually it's obvious from the body of the email, but it would be nice if the tooltip indicated what you were toggling to when you hover over the markdown button.

But overall, worth every star. Thanks again!

This review is for a previous version of the add-on (2.8.1). 

Great writing aid Rated 5 out of 5 stars

I love this tool for writing blogposts in wordpress and converting them on the fly. As a bonus, it even works with notes in the Zotero reference manager. Indispensable for anyone writing in her/his browser — thanks!

This review is for a previous version of the add-on (2.8.1). 

Rated 5 out of 5 stars

You do not have to be a coder or programmer to need this neat add-ons.

Usage is pretty simple and the result is beautifully neat.

Highly recommended

This review is for a previous version of the add-on (2.8.1). 

Brilliant Rated 5 out of 5 stars

Simple yet powerful. This has been really useful for sending snippets of code over email

This review is for a previous version of the add-on (2.7.2). 

So Necessary Rated 5 out of 5 stars

Wonderful stuff! All of a sudden email became a viable development communicator without needing attachments. Thanks.

This review is for a previous version of the add-on (2.6.4). 

Perfect and Long Awaited Rated 5 out of 5 stars

So far, this works like a charm. Thank you very much!

This review is for a previous version of the add-on (2.6.3). 

Brilliant! Rated 5 out of 5 stars

I don't take time to review typically, but this is a fantastic add-on, esp. for developers, researchers, and lots of folks who'd rather have full control over the layout of their HTML e-mails and don't have time to mess with 1/2-baked HTML editors and clunky toolbars. I have wondered for years now why not more e-mail clients would embrace this feature.
I would vote for adding support for **Markdown Extra** syntax, for tables, footnotes, ToC and abbreviations -- but it's a great functioning add-on as it stands.
Thank you to the author.

This review is for a previous version of the add-on (2.5.0). 

Thanks, and Markdown Extra

Thanks a lot for the review!

Markdown Here depends on Marked.js for Markdown rendering, so support would have to be added to it for Markdown Extra. There is an issue for it (https://github.com/chjj/marked/issues/27) discussing exactly that. Fingers crossed.

Simple and effective Rated 5 out of 5 stars

I just installed it today, but so far it looks perfect. Simple, effective, and easy to use. Well done!

This review is for a previous version of the add-on (2.1.0).