I would be wary to predict a mass exodus from currently popular social networks, but after playing around with Ning in the last few days, I'd say it could easily steal users from MySpace. Ning lets you create your very own social network, with custom branding, forums, photos, and videos. Everything is fully integrated and customizable with really slick looking themes that put less focus on individual user profiles, and more of an emphasis on group sharing and communication.
Compared to MySpace and Facebook, you still get to create and manage an extensive personal profile. The main difference is that Ning isn't just a network of profiles; it's a network of groups. Each time you join one of these groups, your profile can be customized with information that's pertinent to that group, making your profile a little more dynamic, depending on which users are accessing it. This allows more room for creativity and interactivity with other users.
Adding media to a Ning page is really simple. Ning hosts videos and photos itself, with really simple uploading tools that let you upload content straight from your hard drive. You can also point to sites like YouTube, Google video, or Flickr to incorporate media from other sites, although you have to jump through hoops to use Flickr (other sites, like MyPunchBowl and SplashCast, make it much easier). There are two core uses for Ning: Mingling with large groups of people who share similar interests, and establishing smaller community groups for your friends. In either instance, you can sign up with your Ning ID, a login that's shared throughout the entire Ning network. It's a little bit like Blogger, which lets you contribute to multiple blogs with the same networked identity.
Ning offers premium services that come at a monthly cost. You can add your own advertising, use a custom domain, and bump the amount of storage and bandwidth for uploaded media. At the free level, each Ning networked site is given 500MB for private content and 5GB for public content, which should be plenty for most small groups but has the potential to fill up with large groups.
Ning has a really fresh feel about it. There is an incredible amount of customization and potential for people who want to create a community site, but don't feel like jumping through the hoops of buying a domain, purchasing a hosting plan, and finding someone to code the project. While you do have to give up some of the freedoms of running your own site, Ning offers a really great sandbox for the casual user, and those seeking more than a sea of profile pages.
Webware's Ning can be found here.