Flickr!

You all know about Flickr, right? If not, go there, have a look around. I'll wait, honest.

Right, you're back? Excellent. Flickr is a great way of sharing your photos - and that, I think, is how most people use it. But on top of that, it also serves as a social network of sorts, and you can find people you know and see what they're sharing as well as finding new and interesting people's photography. You can join groups of people who have similar interests (both photographic and not), there are a lot of regional groups as well - great for sharing and finding photos of your home town.

Personally, I put my favourite photos up there - the ones I take, and really like at the end of the day. I'm always looking for feedback, ideas on how I can do better (either when taking the photo in the first place, or afterwards, in Photoshop).