I'm comparing our best search traffic month in 2011 (March) with our current traffic (April)and have seen significant declines in traffic, despite no change in our rankings or even improved rankings for the same terms.  Trying to sort out an explanation. We have been a white-hat SEO site since our inception over 10 years ago.  Our SEO consultant doesn't think we've been affected by any algo changes, at least not to any significant degree. My only explanation for this possibly anomaly is: decrease in the use of the KW terms in search over time (how to determine?) generalized increase in PPC instead of organic search driving traffic possibility that Adv Web Rankings is no longer accurately collecting SERP rankings Does anyone have any other thoughts or considerations that might explain the decline in traffic, despite maintenance or improvement in rankings? Thanks.

Since the launch of our newly designed website about 6 months ago, we are experiencing a high number of 500 server errors (>2000). Attempts to resolve these errors have been unsuccessful to date. We have just started to notice a consistent and sustained drop in rankings despite our hard sought efforts to correct. Two questions... can very high levels of 500 errors adversely effect our google rankings? And, if this is the case,  what type of specialist (what are they called) has expertise to investigate and fix this issue. I should also mention that the sitemap also goes down on a regular basis, which some have stated is due to the size of the site (>500 pages). Don't know if they're part of the same problem? Thanks.