Google+ Keyboard Shortcuts: Some of the same keyboard shortcuts that worked in Gmail also worked in Google+. Here's what seems to work so far...
Formatting Text
Turns out they are using a wiki style convention to format text:
BOLD - write text between *asterisks* to get BOLD
italics - write text between _underscores_ to get italics
strike - write text between -hyphens- to get strike
Moving about the stream
J move down one post from highlighted post
K move up one post from highlighted post
<SPACE> scroll down one screen
<SHIFT> + <SPACE> scroll up one screen
Comments
<RETURN> opens comment interface in highlighted post
<TAB> + <RETURN> closes and posts comment
Misc.
Q to jump into chat mode