To get to the global theme settings page, navigate to admin/build/themes/settings/global. As stated at the top of the page
These options control the default display settings for your entire site, across all themes. Unless they have been overridden by a specific theme, these settings will be used.
That statement is true for the "Toggle display", "Logo image settings", and "Shortcut icon settings" field sets. However, for the "Display post information on" field set it is not true. This field set is the only place that determines whether Drupal will fill one of the variables ($submitted) available to node.tpl.php for a given content type. So, while you can customize a theme to not display $submitted (by modifying node.tpl.php), Drupal won't even fill the variable for that content type if you don't enable it. (You could use template.php in your theme to format the variable and make it available.) Don't worry if you don't understand the references to node.tpl.php and template.php; using these files is an intermediate/advanced topic. Just remember that this is where you need to go to control whether to display the submission information. Also, be aware that this setting gives another example of how you can make use of different content types.
[Note: this variable has been deprecated in Drupal 7. Inspect $display_submitted to determine whether to show the submission information. The submission formatting is done manually in the node.tpl.php file.]
The API documentation provides information on most of the variables configured through the "Toggle display" field set. There a just a few points that you may need clarified.
- "User pictures in posts" and "User pictures in comments" determine whether the $picture (renamed $user_picture in Drupal 7) variable is going to be filled in node.tpl.php and comment.tpl.php.
- The "Shortcut icon" checkbox determines whether Drupal will display the "favorite icon" next to the URL in the browser.
- The "Primary links" and "Secondary links" variable operate independently of the preconfigured blocks. Themes use these variables in the page.tpl.php file; the blocks are built without reference to these variables. In other words, it is possible to "disable" primary and secondary links and still be able to use the blocks. I recognize that this is probably as clear as mud. An easy way to understand it better is to play around in the Garland theme by changing the settings and displaying the blocks on the page.