Well :SIDEFEED:, :BROWSERTITLE: are special keywords used in the html template file that reference back to the php variable stored in your database's setting variables. They are like placeholders in the template file, way too complicated for beginners to play with. If you want to create a variable of your sitefeed(sidebar) and browsertitle, use these instead:
PHP Code:
$sidebar = getsidebar();
$browsertitle = grabanysetting("browsertitle");
This will work out equally well, and it is good for beginners to use and learn programming. Lemme know if you encounter any further issues.