MyOracleSupport and Community sites should share login info in both directions
Search on MyOracleSupport and you get links to documents and community discussions by default. Unless you have logged in to community.oracle.com in the last few hours, clicking the link to a community page in the search result and your browser does not show the content of the discussion. It would be nice to at least show a prompt for Login to Community in the big blank space. It took me a while to figure out I have to explicitly login to community.oracle.com in order for the search results to show.
The opposite works fine. That is, I can login to community.oracle.com first. Then MOS can be used without logging in again.