u should update the content more related to your keywords i guess - my forum is going up and down in certain keywords, i wouldn't call it something "big" its just normal
Use this forum to submit to 100 directorys a day, for 1 week, and you will notice a increase over time from google. Rob
check your keyword density against your competitor's keyword density... Sorry Rob but this is probably the stupidest thing he can do
Keyword density doesn't matter much anymore unless you're completely spamming your keywords all over the page. Submitting to directories always provides my new websites with a quick pump of link juice. It won't rank anyone at the top (especially if it's a competitive keyword), but it can help.
Just keep on building backlinks from quality website and them related and higher page rank, Quality links is the best you can get and it's even better if it's one way links pointing to your website, there is a lot of topics telling you how to get one way quality back links in this forum.
Actually keyword density matters again since google just changed it's algo to punish sites with a lot higher density than their competitors. Look it up... It changed in the beginning of this month.
Are you pages completely deindexed or just dropped in positions? Do you continue to build backlinks and publish unique content?
Try to get some really good links that will help hold your site and not fluctuate. Like Yahoo directory, DMOZ, Best of the web, and try to get a good mixture of links...Articles, press releases, one way links, blogs, forums, reciprocals...But mainly work on gaining authority site links if possible.