We have a site that was previously run on Wordpress on a different host, but has now been switched to RiVista (a proprietary CMS). The site was cut over a week or two ago.
I realize that a drop in impressions isn't quite as big a deal as a drop in overall clicks, but simply showing up in more SERPs could still be a source of new site users, so it concerned me.
The domain of the site remains the same, but some of the long time urls have been moved or removed in the site, causing alot of in-bound links to fail. I'm working diligently to go through the list of external links and get 301 Redirects setup to relinquish these external links; but I was just wondering if maybe this was somehow related to the sudden drop in overall impressions?