Ploggle is a site where people can collect photos and videoclips they take with their mobile. You sign up for free and then you take a picture with your mobile and send it to Ploggle or your can send images by email.
All in all I think Ploggle is great. I happen to know one of the founders, Daniel Light, from the Kung Fu club. I know that he is working hard on it and recently they've updated the code quite a lot.
The site is really user-friendly which of course is highly appreciated. From a marketing point of view I think they do a great job making it easy for people to sign up. The service is free but if you want to upload more than 30 pictures you'll have to pay a small amount. You can also password protect uploading of pictures.
Some of the great features I like: