Today at WWDC 2015 in San Francisco, Craig Federighi announced two new features being added to Safari in the next version of OS X.
"Pinned Sites" allows you to pin websites in much the way that Pinterest lets you pin images. On the tab bar, Federighi demonstrated how he could grab any open tab and drag it to the left edge of the screen. There, it transformed into a tiny tab that became a "pin" that will reside in that spot in the browser for as long as the user wants. It's a quick and easy new way to get to your most frequently visited websites.
"Tab Muting" is exactly what it sounds like. You're surfing the Web and suddenly, music or audio begins playing. Where's it coming from? A tab running in the background in your browser, of course. Probably from an ad in that tab. Tab Muting gives you a single-click solution for getting rid of the offending audio. When audio plays from a tab you're not in, Safari puts a small icon in the address bar that allows you to mute all background tabs at once. A second option lets you go straight to the tab that's producing the unwanted audio.
OS X El Capitan is expected sometime in the fall of 2015.
Stay tuned for more updates from WWDC 2015.