(This post is more than a decade old, but here’s what word was, then.)
Don’t count on it…
At least not directly. One of the oldest tricks in the search engine optimization bag of tricks is to creatively link to your site from other sites. Will posting links on social media outlets like digg.com, facebook.com, twitter.com and myspace.com help pass SEO juice to your site? It’s a complicated answer that’s closer to no than yes.
What’s the social media SEO story?
I’ll focus on four of the most ubiquitous social media outlets to provide a summary of sorts.
Facebook and SEO
Sure enough, most of it is behind a wall of authentication and other link obfuscation, but the “pages” are more or less public. While you don’t have control over the link anchor text, links are still real links on pages, while links on profiles are opened in obfuscated URL frames and are hidden behind authentication nonetheless.
So using links on your and/or others’ “pages” works a little for SEO. Links from profiles and walls don’t help SEO at all.
Furthermore, though not SEO, Facebook’s ads are some of the most flexible and targetable PPC around. You can really hone in on a demographic with specific interests and other criteria, and then choose PPC or PPM models. Etc.
Myspace and SEO
AFAIK, all links are obfuscated.
Furthermore, when sites obfuscate links e.g. msplinks.com/dsdf07dsf70detc.
they don’t need to even bother with nofollow rules, as the link is worthless anyhow.
Twitter and SEO
All twitter links are nofollow
Most links are also compressed, so even if a SE decides to register them, they’ll be obfuscated or at the very least, truncated.
But just as in FB, twitter can be a good SEM tool, even if it doesn’t directly help SEO.
Of note though, Ask.com does not pay attention to nofollow, allegedly.
Digg and SEO
Submitting pages to Digg *can* be SEO helpful, indirectly. If you pick a niche phrase, e.g. “Hawaii hotel with handicapped access” …And use it in both the title and description, the digg piece will inherently rank well, and it SOMETIMES directly links to your page. Is that link nofollow? It’s a tough answer. Digg recently implemented a diggbar that most certainly frames the URL and passes little or no SEO juice. If you’re logged in, and (like me) turned off the diggbar, then it *seems* that link juice is passed. I.e. they do NOT use nofollow. But keep in mind, most people use the link-juice-vampire bar.
SEO and Social media summary
There are scant direct social net SEO opportunities out there. But even when not directly benefiting SEO, the visibility, engagement and brand awareness doesn’t hurt!
Here’s a slightly dated (2007) list of social sites that do NOT use nofollow.
Not sure how accurate it is anymore.
If you have any questions, just post in the comments. If you need SEO, click the link! My name’s Dan Dreifort, and I do SEO.
Dan Dreifort 
Wow amazing post! Thanks so much for sharing.
The only thing this blog is missing is some tasty Google ads. And maybe some nekkid grandmas. What’s up.
Nekkid grannies coming soon. I’ll move this blog off of wordpress.com someday. But until then, no AdSense. They don’t allow it. 😦
I think you should develop a course for a college, technical school, internet based whatever. You obviously know a great deal about SEO and should be getting paid for imparting that knowledge to others. IMHO.
You’re sweet. And you’re right. A few times a year I post job listings on craigslist and other sites to find assistants. I receive several queries from recent grads, but I’ve yet to find a college that’s adequately preparing its grads for the world of SEO. I’m confident that in a single course I could impart more than any school teaches in four years. Here’s the rub though… I don’t know of many colleges that can afford the services of knowledgeable SEOptimizers. Why would a qualified consultant trade an ideal gig from home for an underpaid 9 to 5 in the world of academia? I.e. I don’t know if any schools can afford me. Instead, I rent myself out to corporations. I can train a slew of developers and webmasters in one fell swoop over a couple of days. Or, I can do the actual work remotely. Low overhead. Big savings.