I don't see any topics about this here and can't search the preview site but what's the deal with the old special BBCode button that brought up a drop down list of BBCodes for people?  

Do we have to create a toolbar button for everything we'd possibly want now, instead of having that button?  And on the mobile version, how do you choose which ones show up and which ones are hidden based on the size of the browser? 

You have to install CKEditor plugins (you can create basic replacement ones in the ACP easily) in order to introduce new formatting options.

 

You can control which buttons are available in the ACP Toolbars customization page separately for Desktop, Tablet and Mobile views.

Oh that's awesome!  I'm mainly interested in easy post formatting options for using the mobile skin so I can get my users away from Tapatalk. The easier I can make for them to be able to embed Tweets and have the nice Twitter look, embed Youtube videos and be able to do simple stuff like bold, italic, etc. the better. 

Thanks @bfarber