Traffic from Google Search engine.

Have you re-designed your website? May be major changes in content of your site also affect your search engine rankings.

If you are talking about your article site, the problem may be from "duplicate content". Google does not want 1000's of the same page in their index and are trying to filter out duplicates.

You may have two things working against you in this way.

1) I think the article site is provided to many, many sites and so it has a pattern that could be recognized as a "template", and if the page titles and meta tags are the same as other sites, I would think it would easily be flagged as "duplicate". I would consider changing the page titles and meta tags to be something different and your own if they are not already. Then I would change the text on the pages that came with the original site, and add more content to the pages if you can.

2) If you are taking articles from other sites, this too could be seen as duplicate content and not considered very "important". In this case, you don't want to edit the articles that have been created, but you could add some comments or add additional resource links for the topic of the article. I would also edit the page title and meta tags to be different and generate more interest in what the article is about.

If you have not been submitting your site to search engines and directories, I would also work on that. This should increase the one-way links to your site and that should also help.