A new feature in Safari for El Capitan is the ability to save web pages you frequently visit as a pinned tab. Pinned tabs will always appear to the left side of the Safari tab bar as small icons. You can access them like other tabs, but they will automatically appear on any new Safari window you create. If you click on an external link in a pinned tab, the other site will open in a new tab. Plus, pinned tabs are persistent across all windows, matching the same page and page position.