As the SharePoint 2010 social features are limited, either custom code or a 3rd party add-on is necessary. Here a nice post about Extending SharePoint 2010 Social Features with custom code.
Extending SharePoint 2010 Social Features
Thomas Maeder | thomasmaeder.com
This is the website of Thomas Maeder with a blog about Intranet, Digital Workplace, Digital Communication & Social Collaboration topics.
Thomas Maeder | thomasmaeder.com 