For sharing photos? Flickr, no question. Not only do you own the rights to your pictures, Flickr also does it's best to protect your images from being copied. There's ways to organize your photos, in sets or albums, and you can easily share them with others. There's also a nifty feature (that I'm absolutely in love with) that lets you display what type of camera you used, lens, and what your settings were when you took the picture. The best part is that Flickr gets all this information from your files automatically, so there's no work required on your part. You can browse other user's amazing shots that are featured on the website (updated daily) and check out what types of cameras they use/settings to get particular shots. You can learn a lot from other users by doing this. If you're interested in a particular camera or lens, you can also learn more about it on the website, it also provides pictures other users have taken with that lens/camera.
It's also kind of like instagram in a way, you can follow your friends and such.
Honestly, Flickr is just the best photo sharing site; hands down. Anyone else who says otherwise should actually give it a chance.