Focussion is a Different Kind of Photography Community
One of the biggest problems with websites designed to host and share your photos is that, for the most part, it's a solitary experience. Focussion is a site that's attempting to change the way sharing works.
Most hosting sites allow you to upload as many photos as you've got, rather than picking a select few. They also fail to encourage the browsing of other people's accounts, which is essential to build an actual community. Focussion doesn't just encourage you though; it doesn't give you a choice.
The site works on a credit basis. You've got 250 credits to start with and each photo you upload takes 25 of those. Once you're out of credits, the only way to get more is to comment on the photos of others. Each comment earns you five credits.
This system, according to Focussion, practically guarantees that other photographers will look at and comment on your work. There's nothing that guarantees helpful comments, but encouraging comments and constructive criticism are encouraged.