This "folksonomy", or community categorization via keywords, is what makes flickr unique in the photo-sharing world. People are collaborating, sharing their photos, and helping each other to classify them as well. This is in sharp contrast to many sites that simply lock you into their pre-defined templates and spaces.

No lock-in
flickr doesn't want you to have that locked-in and confined feeling you get with other photo sites. Your photos are yours, and you should be able to get them out of the system just the same way as you put them in. They simplify this by allowing you to go to your own photo pages and download the full-size version of any one of your photos, like you see in Figure C.

FIGURE C

You can download your original file as well as other sizes. Click picture for a larger image.

They're even working on a way for you to download all of your files in one fell swoop.

flickr also opened up their API to outside developers for free, complete details can be found at http://www.flickr.com/services/api/. This allows people to create various tools to extend the functionality of the service in additional ways. Many tools have already popped up around the Internet that do everything from creating a rainbow montage of photos, to allowing synchronization with Apple's iPhoto.

It's this willingness to embrace the community, rather than snub it, that's gained flickr many fans, especially among bloggers.

Blogging made easy
Blogs (short for Web logs) are online journals that have really taken the Internet by storm in the last couple of years. According to Merriam-Webster, "blog" was word of the year for 2004. flickr realizes this and really tries to cater to the blogging community.

You can tie your flickr account to many of the most popular blogging tools on the market today, and publishing your flickr photos to your blog is as simple as making a couple of clicks. Even cameraphone users can set up the system so they can send pictures directly from their phone to their blog via flickr.

The flexibility doesn't end there. Each user's photos, known as their photostream, can have syndication feeds associated with them. These are RSS or Atom feeds that allow users to subscribe to a person's photos via RSS newsreader software.

This method notifies a user whenever someone posts a new picture to their stream. There are feeds for most areas on flickr, so you could subscribe to a stream with photos that have a certain tag, all the photos in a group stream, or even the textual discussion threads in a group.

Groups
The group concept is an additional level of community within flickr. There are groups that share certain types of photography, groups according to cities, countries and regions, sports groups, groups based around events, and even groups that only contain private circles of friends or colleagues.

Groups act as a shared location for people to post in a discussion forum, and for members of the group to add pictures to a shared pool. Anyone can create a group or join as many groups as they want to be a part of. Groups, shown in Figure D, can even be made public or private, so if you wanted, you could set up a private family group where all your aunts, uncles, and cousins could add photos to a shared space.

FIGURE D

The Groups screen. Click picture for a larger image.