If you are a photographer, you have probably heard of Flickr. Flickr is a large, primarily photo sharing, community made up of photographers from around the world. It allows you to easily upload, organize, share, and discuss your photos and photography in general in the many groups around the site. Free accounts are limited to 200 photos (unlimited bandwidth) and 1024x768, but pro accounts can store an unlimited number of photos, with most at their original sizes. Flickr also allows you to share videos (including 720p HD) of under 1 minute. If you plan on using Flickr, you will quickly find that upgrading to a pro account will be very useful.
Bottomline: Perfect for amateur photographers looking to share their photos and get feedback.