Strange Hit on serps - Need some advice on where to go from here.

Hey guys, I have been ruing a multi niche site for the past 6 months. Everything has been fine in the past month I got a large increase in traffic due to the amount of work I have been doing to the site. This is pretty much similar to what I have done in the past. Building strong web 2.0s and the odd few links (relevant) and social links. Now this moing I logged on to find out my normal 1000 or so unique visitors per day is now at 80. At first I thought perhaps my site has been de indexed or some kind of negative seo.

I checked my serps and found out 99% of my links and main keywords for them had gone from the top 10 to not even in the top 100. There is still the odd keywords here and there but these are keywords that look more accidental than anything. I did the usual site:mysite and found all my links are still there just dropped it the serp rankings. The most pain in the bum thing is that my site name doesn't even appear in the top 100.

Now I thought ok lets see what webmaster tools has to say about this... Nothing, not a single word or message or any strange activity. Even my backlinks are near enough the same they have been for weeks. It is quite odd.

So ive got to thinking is it something ive changed. I recently added analytics to my site to get more of an understanding of the visitors I was working with Ive had it up for around 3 days. The only problem it was bugging on my main page of my theme. It was showing the code on the front page so instead of finding a work around i just made a new front page via posts. Made it a sticky. Then showed a few of my posts on the main page also.

Now i have another 5 multi niche sites that have not changed serps but i did not change there front page or add analytics. Which leads me to think is this the problem? Its just odd to jump completely off the top 100! instead of lose a few pages. If anyone has experience anything similar or may have some explanation as to whats just happened then id like some advice.

Im not giving away niches or sites. Just want some advice. This is not a black hat nice and I don't use black hat methods for these sites.

The steps I have done so far is change my site into a static page and removed the stickies and post list. I have checked and removed any links i don't like the look of which was just 1. So bit stumped where to go from here.