Facebook LIKE Button

I've been experimenting with various social button plugins such as addthis and sharethis and I'm disappointed with their lack of use. My admins are non-techie and their visitors appear to be the same. Some pointed questions of my admins and random visitors makes clear that almost NOBODY knows what these are for. Tens of thousands of impressions over the past year and my social button click-rate is entirely insignificant.

Similarly, trackbacks and pingbacks are beyond the comprehension of my admins. Motivation is low for active commenting as they consider each other competitors, but they say they would support each other with a "Like" or something similarly easy and benign.

Moreover, they also don't know how to ask their visitors and advocates to promote their posts. It would be a shame to ignore 500 million interconnected would-be readers. So, I'm looking for a simple "I like this" Facebook button with a trackback-like: "Joe Blow likes this / Jane Doe likes this..." functionality linking to the blogs' mapped domains. Hopefully I can increase usage by drawing a line straight to the lowest common denominator of social interaction.

I found the plugins linked below (and a few others), but none of them mention WPMU compatibility, nor do I know how they work with mapped domains and BuddyPress. Does anybody have any experience with these or similar?

http://blog.gunnjerkens.com/2010/04/facebook-like-plugin-for-wordpress/
http://www.my-tapestry.com/i-like-this/
http://blogicthink.com/i-like-this-wordpress-plugin-facebook-like-wordpress/
http://wordpress.org/extend/plugins/like/
http://wordpress.org/extend/plugins/fblikebutton/screenshots/
http://wordpress.org/extend/plugins/wp-facebook-like/
http://wordpress.org/extend/plugins/facebook-like-button-plugin/