netmeg - 3:57 pm on Apr 14, 2011 (gmt 0)
Ok, you need to look at your analytics to see WHICH sources of traffic may have changed patterns, and if it's search, then which keywords maybe have dropped. Do you get a lot of referral links from other sites? Is it possible that one of them has got a bad link to you?
This is like forensics, so approach it like it was a new CSI series.