I am a devoted Flickr user. The problem is that long before Flickr ever came along I was a devoted SmugMug user. So now I've got my photos split between SmugMug and Flickr - and not just a few photos, but gigabytes of photos. Generally I prefer Flickr, but SmugMug has two features that stand out: completely customizable templates, so I can add my own look and feel, and a shopping cart with a wide range of products, so that you can order mugs with pictures of my niece (which include a tiny markup that goes to her college fund). Flickr, on the other hand, has the wonderous tagging that makes it a folksonomy and my all-time favorite feature, mo-blogging: posting photos to your Flickr feed from the your cell phone.
