It's so depressing when you are ranked #4 or #5 in Google for a popular search phrase, then you check one day and you suddenly fall off the map almost entirely. All three search phrases that I was ranking high for, I have now all but disappeared. I know it can't be because of anything on my site that is against Google's terms or philosophy. So why does this happen?
I had been about #5 for 'Nintendo' for years, and on the last update I droped out of the results. Converting to wiki is the only thing I can think of that might of caused it.
Happend to me too, I was on page one on all search engine, then some how I ended up on page 3, don't know why. At least you learn to try to get traffic from all over the place, don't just depend on one place.
This also happed to me then i posted some articles and got a few nice backlings and was back on the front page again. Keep posting new content.
Google constantly is updating their algorithm, you guys may have just fallen victim to a new change... that they are not telling anybody about