SPMUG 640  Show Status Bar
When you select a link in Safari, if you have "Show
Status Bar" selected, there is a message in the Status Bar telling you
what will happen if you press the cursor on the link. By default, Safari
will open the link, replacing the current page with the selected page.
However, if you hold down various modifier keys (Command, Option,
Control and Shift) while selecting a link, interesting things happen.
For example, hold down the Command key + the Shift key and the link
opens in a new tab. Just hold down the Command key and the link opens in
a new tab behind the current page. Try other modifier keys for other
interesting results.