How to preview a web link without leaving the Mail app

Got an e-mail with a link you simply must click (hopefully not a spammy link, of course), but not quite ready to leave your inbox?
Good news: there’s an easy way to sneak a peek at a web link without leaving your Mac’s Mail application.

Click the little arrow icon to the right of a web link to preview the page without leaving your inbox.

Just hover over the URL with your mouse until a little arrow icon appears to the right of the link.
Click the arrow, and a preview of the web page that the link is pointing to will appear in a pop-up window.
You can scroll within the preview window, click any of the links (although doing so will take you out of the Mail app and into the Safari web browser), or even save the web page to Safari’s “Reading List.” 
Want to open the page in Safari? Just click the “Open in Safari” button.
And what if you’d rather just keep reading your email?
Easy: just click anywhere outside of the preview pop-up to make it disappear, then go back to your messages.