Maybe your site's ranking in the search engines is changed. Try to work your way up to the top of your keyword again and see if the traffic comes back again.
Google is now focusing only in unique content and relevant backlinks. Don't try to use black hat technique to get ranking this way you can penalized by Google.
Google algorithm are getting better and better that the competitions among websites are getting tough.
Google merely states that the update is designed to reduce rankings for low quality sites, sites which are low value add for users, copy content from other websites or sites that are just not very useful.
Mix up your backlink sources & ensure that your content is unique. If anything, the recent "slap" on content farms / sites with nothing but scraped content is a good thing - as long as you've got legitimate, unique content.
I read about this on Lifehacker. Gist of it is: - Only having spammy backlinks = bad - Being a "content farm" (autoblog? someone tell me what a content farm is.) = bad - Suspicious number of links from Twitter and other social sites = bad I believe the days of easy online money are fading away quickly. If you write quality content that people will want to read, you will get natural traffic in no time.
Autoblogs are actually doing better according to most people. All the article directories got severely devalued. I mean SEVERELY devalued. That's what the update was really about.
Although Google does not officially confirm it, this algorithm update tries to remove so-called content-farms from the search results. Content farms are websites that invest as little time and money as possible to generate a large amount of content created by authors who are usually not familiar with the topic they write about. Google's anti-spam team is serious about eliminating spam from the search results. They announced that the are working on "many more updates that we believe will substantially improve the quality of the pages in our results".