Flickr is an image and video hosting website launched in 2004 that became popular for photo sharing and social networking. It allows users to upload, store, organize, and share digital photos and videos, either publicly or within private groups. Users can also comment and tag photos, automatically post photos to blogs, and connect their Flickr accounts to other social networks. With over 18 million users uploading around 5 billion images by 2010, Flickr helped drive new forms of online photo organization and social sharing.