Keywords are attached to the album level, so you can easily tag a series of pictures. Let's say you go on a hiking trip and upload the pictures to C2U. You can then write a postcard:
'"Check out our trip today! Keywords: Hiking"
Members can then easily find all the pictures quickly.
Keywords will also search picture description and username. Check it out! It's the new link "Pictures"
If you notice any bugs or have any suggestions, you can add a comment to this post.
Note this has replaced the "members" functionality.