Facebook is coming down hard on automatic tools - so stay away. Even manually, they have begun blocking the posting of the same content that has already been posted in a number of groups. They also automatically check how many times you comment with a url and block that too.
The following is the best method for Facebook:
Fan Page Content
Share to Limited Groups
Comment without url (only give urls to interested people via PM)
Leverage Cooperative posting services that use real people to share content to groups.
Have them SPIN your content or do so yourself using NOTES and have them share your various note spins and cloak urls for each version of the Spin.
Any type of duplicate content will endanger your ability to post, comment and then your account is closed.
Focus on quality content and helpful commenting and direct assistance to interested niche participants - here is where I amke the most money from Facebook.