<dialog> is awesome, especially when combined with Invoker commands or `popover`.
<menu> does nothing, it's just another name for <ul>.
<ruby> is going to be featured in my next article: You don't know HTML…Semantics.
I'm debating whether that one will be one or two articles because I'm going to be covering everything from <ruby>, <bdi>, <bdo> all the way through <var>, <kbd>, <samp>, <cite>, and <q>.
After that one, I'll probably have something like, "You don't know HTML interactions" or something to cover <dialog>, <popover>, and the Invoker API.
So sit tight; it's all coming.
I like to ask people what they imagine <ruby> does, because I certainly didn't guess right.