People who are afraid of losing their photos. Flickr gives free to use completely a terabyte of memory. That once saved my photos from total destruction. If you are a curious person , and not just careful, Flickr offers a huge number of original photos from around the world. The number of unique works is just obscene. And one life is not enough to see all perfect shots. It is possible to add interesting work to your favorites and to see what what professionals add to their "favorite". In general it is essential as a platform for inspiration . Such a large number of photos creates true known issues: sometimes it is difficult to separate the wheat from the chaff, a good shot from hundreds of mediocre. This search draws sometimes not less than contemplation. At least for me. Advantages: a large number of works, the ability to download the original size, globality, the presence of groups by interest Disadvantages: a lot of anadromous and random photos.