it's like a website where you can load up your photos, then you can join groups etc. and have discussions, send the photos to blogs etc. i find it easier than piczo because it's just so much quicker to load photos and easier to organise, clearer layout etc. my site is
http://www.flickr.com/photos/hoxie if that makes it easier to understand how it's laid out! there is a limit to what you can do with a free account, but even then i find it so useful!