Over the weekend, I had a few hours while the babies were napping, and wanted to do a small fun project. So I added Markdown support to the post/reply boxes, along with code syntax highlighting in the archives.
Markdown, for those (most) who haven't heard of it, is like plain text, except that it lets you include some formatting with it. There are a lot of places online that explain what Markdown is better than I can, like http://whatismarkdown.com. I think it's much better for conversations than HTML messages, and yet neither Google Groups nor Y! Groups support it.
And with Markdown, if you're including a bit of source code in your message, you can tag it and it'll display nicely (this is called code syntax highlighting). The nerds, like me, really like this (and multiple people have asked for this feature in Groups.io).
Anyways, if you want to post using Markdown, you now can. If you don't, nothing's changed for you.
(I'll be going through all the messages from this weekend over the next couple hours).