For one of my clients, traffic doubled in the last two weeks. The site has been up for 8 years. There is a solid jump in traffic.
Why? Two weeks ago, I built a Facebook strategy for the site. Customized landing page in fan page; lots of photos and info in the tabs; Facebook PPC; and added Facebook comment boxes to 500+ pages at the site.
When someone writes a comment in a Facebook comment box on one of the site's pages, that comment shows up on the person's Facebook page. That person's circle of friends see it. A second comment sends the link a second circle of friends. Just by adding comment boxes, you get massive exposure.
Facebook ads also work well: you can target by age, location, interests, and so on. Get started with $50 in free credit: use the code fb-adtech-sf when setting up your ads (I get nothing for passing it on).
SEO in Facebook is interesting. I met with a company a few months ago. They have 2m pages with auto-generated meta-tags and headers. That's cute. I asked them "so how are you going to SEO for Facebook?" No meta-tags, no link counting, no backrubs, no pagerank, no page-format indexing. They built their entire business model on Google.
Google wants to be secretive and insufferably arrogant? They can buzz off. Try Facebook. It works. I'm rolling out Facebook strategies for all of our clients.
Another tip: kids prefer Bing. Why? It's prettier. Isn't that funny? It's not about algorithms or speed. It's pretty that works.