None that I can specify I just don't like the feel of it. Probably because I was very used to Photobucket before I tried fliker. It's probably easier to say what I like about PB I like the way you can create 'albums' in Photobucket and can continue to down load any photo directly into them if you consider it suitable, and it has plenty of space for tags though I don't use them. It's great for bulk uploading and has a better editing suit than I have on my computer. Perhaps if some one does reply with their reasons why flicker is best you can compare them.