How can My City My Voice improve it's social networking activities?

My City My Voice took some time out today to do some critical analysis regarding our various social networks.  We have Facebook (because it's so popular with our artist and community members), youtube (for sharing video), soundcloud (for sharing sound), and of course this blog.  We are thinking about ways to better share our process with the public and interactively engage people in this conversation about community, art, new media, and our summer themes of story and mapping. 

How can we better use the internet for social media? How do you use social networking and new media tools?

Specifically we've started by trying to find a better way to share our visual art from sketches and collage to digital photos and community maps.  What are the best social networking sites for visual art? Photos?
Is there one that can do both for us?  Give us your top three (free!) visual art/photo hosting sites.

Here are a few that I've found to consider:
Visual Art
http://www.myartspace.com
http://www.artreview.com
http://www.artmesh.org
http://www.artslant.com
http://www.artlog.com
http://www.independent-collectors.com/
http://www.artselector.com
http://www.rhizome.org
http://www.labforculture.org/en/labforculture/browse
http://www.artbistro.com
http://www.deviantart.com/

Photography
flickr.com
snapfish.com
photobucket.com
fotopic.net

This is our primitive form of social networking; mapping paths through string, sound and story.