The Social Desktop (Open Collaboration Services) settings module lets you configure your user accounts for Open Collaboration Service Providers.
At the time of writing openDesktop.org is the first provider that you can use. You can use the web site or this settings dialog to register and manage your account.
The benefit is that you can do more things in “Get Hot New Stuff”: vote for items, become a fan of them and upload new content. A configured account also allows you to use the social Plasma widgets (Community, Social News etc.) to their full extent.
Using the System Settings module:
You can select which provider to configure at the top. Either enter your existing user name and password to let KDE use them. You can verify that these work by using the button
If you do not have an account yet, use the Register tab. Here you need to fill out all fields. After clicking you will receive an email from the server to activate your account.