Main Keyword penalized. And now?

[webg]

Hello SEO comunity.

In one of the sites that I work, our team won numerous keywords in the first searching results.

Unfortunately, on june we lost the most important site keyword. It was a general Word, very disputed, that generated a lot of traffic to us.

The problem: it droped from third to fifty position.

I’d like your help to identify the possible punishments and than find the solutions. What could happened? Where do we start?  Is there any checklist to verify the punishments? What do you suggest to me?

PS:

• We always do a clean job, getting away form the blackhat techniques;

• We didn’t received any notification from Google;

• During two year, the keyword was in the first ten positions.

Actually, I'm looking for an explanation for what happened to me, to get my top10 again.

Thanks

[AdeLewis]

I would second Irving on this.

We got hit with exactly the same issue. After a bit of head scratching our best bet was over-optimisation of anchor text. With a bit of work we managed to get a fair few of the anchor text changed, some removed and we also diluted the exact match anchor text ratio by linkbuilding with generic www.mysite.com type anchor text and the rankings returned after a few months.

[irvingw]

probably a combination of on page overo ptimization and over optimization of anchor texts on incoming links.

[HiveDigitalInc]

I'd love to help but I would have to know the site and keyword, it is the only way. Would you be willing to present it either here or via private message?