500px is apparently where all the cool kids go. I use Google Photos.

(500px has a really weird community. The hive mind likes photos edited to have a certain look, and there are lots of random people that show up to like your photos in the hope that you will like theirs, and they'll get popular enough to be featured on the front page. As a result, I don't use it. My friends on G+ are enough sharing for me :)