It's been about 13 months since Google unleashed the Panda filter and ripped apart the internet heyday of article marketing and link building.
Google's "Panda Update" originally went live on February 24, 2011 and has been refreshed a few times since. Panda is not actually part of the search algorithm, but rather an extra filter that's applied to the Google index.
Periodically Google runs its search database through this filter to weed out bad websites so they won't appear in the SERP. Among that list of bad websites are once popular sites like EzineArticles.com, HubPages.com, thefind.com, and mahalo.com.
These websites aren't actually bad, and you won't get a computer virus by visiting them either. Google filters out these online properties because SEO professionals figured out how to abuse them for financial gain.
Bottom line is that Google wants the internet to grow organically. Ezine and HubPages once referred a lot of traffic to jewelry store websites. Now, instead of writing short articles and posting them on Ezine/Hub or other websites, we recommend writing quality blog entries and posting them on your own site. The long term benefits are far greater.
A lot of organic referral traffic still comes from a few faithful websites. We're still seeing people arriving from StumbleUpon.com, Reddit.com, and even from digg.com. Of course many referrals now come from Facebook and Facebook's Mobile site.
Traffic from these sites comes from bookmarks or links, most of which is created naturally (organically).
If you want to build links for your website, you can ask an army of honest people to bookmark your website on Stumbleupon, or visit your website and click the Facebook Like button you have on your home page. (You do have a FB Like button on your website, right?) (You do have a Facebook, right?)
You could also periodically visit the site http://www.updowner.com/ and see what they have to say about the most popular new websites. As we write this Nugget, Pinterest.com is in the #2 spot for fastest growing websites. Pinterest.com is a great place to gain fresh inbound traffic right now. It might be the next big thing for SEO professionals to abuse, and therefore get filtered out by Panda. It is also is will be a popular stop for people who will want to share copyrighted material just for fun, and the repercussions of that aren't known yet.
Speaking of SEO professionals, if you are considering hiring someone, you should definitely think for yourself and question their authority before spending money. If you're paying for link building (i.e. non organic traffic) then use the Updowner.com website to see if they are link building from sites that are on the rise.
Google changes the rules of the SEO game every day, which is why SEO services can't be guaranteed. The best any of us can do is keep learning and not be afraid of SEO technique changes.