knjemily - 2:44 pm on Jan 12, 2007 (gmt 0)

We experience this last April, May and June.

Site age: 1997
Site size: 1200 pages
Ecommerce site primarily dependant on search engine traffic
Spider activity: normal throughout the entire time.
SERP drop: site wide ranged from 200-bottom of list
No major changes in prior 6 months.
Adding half dozen reciprocal links per month.
No supplemental problems (except those that should be).
Site:domain showed wrong pages high on list.
Site:domain showed thousands more pages than on site.
Most important page in sitemaps wrong.

Suspected problems:
Overly optimized (many pages with same keywords in title and h1)
302 hijack problems
Validation problems (sitemap showed 1 page it couldn't follow).
www vs non-www problems.

During the first six weeks most of the 302 hijack problems resolved, most pages validated, removed some suspicious reciprocals and fixed the www vs non-www problems. Site came back for 24 hours and died again.

During the next six weeks title over optimization was fixed, validated all pages and heavy internal cross linking changed to hierarchal.

At the end of the second 6 weeks, site came back with all of the sitemap and site:domain issues correct. PR went from PR5 to PR6.

Now we are reworking the entire site using css, updating the title, h1, h2, h3 and content for specific keywords (much less duplication), adding js menu while keeping the hierarchal text links, and fixing supplementals with better content, 301's etc. These changes in the sections that have been completed are resulted in old keyword phrases ranking better plus many new keyword phrases ranking in top 30.

We are also looking at ways to improve "natural" inbound links without "buying" them. We are still struggling with this aspect.