JS_Harris - 9:33 pm on May 23, 2009 (gmt 0)

I have a site that shows a saw-tooth graph in which weekly traffic peaks every Tuesday and is lowest every Saturday, the graph shows a steady increase in traffic over time but the same pattern holds steady for at least 8 months.

I figured it was cyclical interest in my topic but now i'm not so sure.

I've been keeping track of what's indexed in Google and I'm finding that the site has the highest number of pages indexed on Tuesdays and the lowest number on Saturdays.

It looks like the sites rankings, both in position and in quantity, drop every Saturday and raise again quickly on Tuesday... and i'm at a loss for why.

I'm not looking at a small site or a limited amount of data, the drop is significant at roughly 18-19% every Saturday. Any ideas as to what could be causing this?