I am sorry FW...EBS
Why? Maybe the owner put the ads there to keep people occupied. Fluffies have to go somewhere to get all their super kewl information. Besides if it was me I would set it up so I could get paid per click ^_^
Inspired by C_A's comment regarding the mobility of the cross quarter days, I've added a link to a chart of the exact sabbat dates to the OP.
A list of reference sites I've found very useful in my path. Endorsed by me, so they've got to be good...