A Cre8asite Forums thread asks a question about the potential SEO or link building impact Facebook can have on a web site. The simple question is, is there a benefit in terms of ranking to have users share and fan your Facebook pages and for you to share information and links with them on those pages?
This site has a Facebook page over here, links are automatically shared. But technically, although Google sees the page the links do not pass any weight. They all go through a middle page and then another redirect, which I think blocks all link passing capability.
That being said, it does not mean that Facebook sharing doesn't help with your SEO efforts. The thing with social media is getting people to see your content that otherwise would not have seen it. If more people see your content, then more people can discuss your content and possibly link to your content on sites that do pass link juice. So although Facebook may not have a direct impact on your rankings, there may be a very strong indirect impact on your rankings.
Let's also not forget how much traffic a site like Facebook or Twitter can send. So keep that in mind also.
I admit it, I do a horrible job of manning the this Facebook page to answer comments and questions. I am not a huge Facebook guy, but I am trying to check in daily now and maybe I will get the hang of it. I am very active on Twitter so feel free to follow me there also.
Forum discussion at Cre8asite Forums.