Here's a handy Safari tip. I open most tabs in the foreground, but sometimes I want one in the background - therefore, I have the "select new tabs as they are created" preference checked. If you uncheck it, the default behavior switches to opening new tabs in the background.
You can open just about any link in a new tab by Command+clicking it. The tab will open in either the foreground or background depending on the above mentioned preference. If you want to reverse the default behavior just this once, Command+Shift+click the link. For example, you have new tabs set to open in the foreground by default. If you Command+click a link, a new tab opens in the foreground with the link contents. Command+Shift+clicking a link causes a new tab to open in the background with the link contents.