Branding on Facebook: Groups or Fan Pages?

Search Engine Journal produced a comparison between two free Facebook branding tools: Facebook Groups, which enable users to cluster around a shared interest; and Facebook Fan Pages, which are like a personal profile page for companies.
Two major distinctions were made:
- Fan Pages are visible to unregistered users and are indexed by the search engines. Starting one may benefit marketers from a search engine optimization perspective, and also help manage its perceived brand value in the social networking space.
- Groups enable members to send “bulk invites” to other users, whether or not they are members. This makes Groups good for viral or events-oriented marketing.
Other key differences:

In contrast, Pages are better for maintaining long-term relationships, improving brand searchability on social media, and interacting with a fan base.
[Story Found at Marketing Vox]
Facebook held 20.56 percent of the social networking market in August, according to Hitwise.