tedster - 3:35 pm on Mar 31, 2010 (gmt 0)
Hello wmexpert, and welcome to the forums.
It is good that you are focusing on your traffic rather than merely chasing rankings. However, when traffic begins to decline, then your analysis needs to become more granular and detailed.
It is essential to look at which specific keywords used to drive strong search traffic but no longer are. This analysis naturally includes which pages were the common landing pages for that search traffic.
Even if you don't have historical ranking data, you can perform those searches on Google today and see where your pages now rank. There is even a chance that your page that used to rank has now vanished for some reason and only a much weaker page appears.
It is also a possibility that something negative has happened in your backlink profile - a few strong backlinks may have been removed, or perhaps an outrageous number of spam backlinks are directed at your site.
There is even a chance that your site has been hacked and is now hosting parasite content that is cloaked so it is not visible to you but only to Google.
We have many discussions here in all these areas. Many starting resources can be found in our Hot Topics area [webmasterworld.com], which is always pinned to the top of this forum's index page. Further help can be located through Site Search [webmasterworld.com]
It's true that sometimes on-page changes will cause a ranking drop. However, unless your changes include change in content or even a change to your URLs themselves, it is unlikely that the root cause is something like a wider page or even changing to a <div> based layout from a table structure.
Number of links on page were increased up to 100%
Was this a change made only to internal linking? And did affect only the Home Page or the entire website? How many total links are there on the page now?