I don't know if this is another A/B test or not, but right now I have no way of using the plaintext Markdown editor while being able to see a live preview of the rendered result.
I am not going to want to have to click on the Rich Edit button just to get a preview and then click back again - over and over.
I'm on a desktop computer, with a proper full-size display: I have more than enough vertical screen space to be able to see the preview and the plaintext box at the same time.
Furthermore, I noticed a bug with the Rich-Edit editor mangling up my hand-written Markdown: in my screenshot, when I wrote-out the first bullet-point (about mutually-exclusivity) I never wrote any backslashes and I left spaces before or after the backticks as-appropriate, but apparently switching to the Rich-Edit mode and back again caused it to change (and break!) my hand-written Markdown too:
It was this:
`left.Foo` and left.Bar` are mutally-exclusive. So if `left.Foo` then` left.Bar == false`.
...and it changed it to this:
`left.Foo` and left.Bar`are mutually-exclusive. So if`left.Foo`then`left.Bar == false\`.


A/Btesting anymore... now it's(A×B×C)/Dtesting. I don't know how the raw metrics from multifactor experiments are going to be useful.