speedshopping - 11:49 am on Mar 23, 2012 (gmt 0)

Hi,

Does anyone have any experience in a domain or subdomain where its pages will rank naturally for a few weeks, then literally drop out of the sky for a few weeks, then reappear back to its normal ranking position, and then fall again etc.

I have had a good look in Analytics and will continue to do so until we find some kind of pattern, but wanted to ask if any webmasters had found a definitive reason as to why this keeps happening, or is it just plain random?

Cheers,
Wesiwyg