EPC dropped like a rock this weekend

yes, another one of "those" threads

[ownerrim]

This has happened more than once and, at this point, I try to just ignore it. But it's definitely irritating to make x for a long period of time and then suddenly make 1/4x all of a sudden, especially when the site in question is about as dead-on as can be and no changes have been made in content, structure, ad placement, or serps ranking.

[adfree]

"also the launch of multiple windows was done so that publishers would not loose anything...'

Don't really see what that would have to do with a decline in ad value.

Also: if there are more ads available and clicks distribute among a broader band (multpile ad units), on top new windows re-funnel traffic back to publishers wouldn't there be more high cost ads available for the ones only running one unit in the same window? But these are hit at the same ratio.

[newbies]

I have experienced a big drop in EPC (25%) since late August after I changed ad layout and a further drop since Sept. 1st. However, since last weekend, my EPC is gradually bouncing back close to what I usually have. Hope it will stay there.

[freedata]

Seems like this drop is pretty wide spread. My sites, on average dropped 25% in EPC. But strangely my CTR increased by 10% (it was X before now its 1.1X) to compensate for part of the loss. Overall revenues dropped by 20%. I don't think it is accidental. Either this is due to allowing of Multibanners (which I tried for one day and switched back to single banner), or reduction in payout percentage or both.

My drop is since last wed (7th) when I tried multi ads for one day and switched back to single ad.
Does any one here who never experimented with multi ads for even once, but still got hit by the drop in EPC? Just wanna make sure my drop is not related to trying out the multi ads for that one fateful day!

[fraudcop]

With double banners I doubled the number of clicks but My EPC remained the same meaning that I lost 5o% revenue.

Since I'm spending all the adsense earnings on Adwords
I suspended a couple of Adwords campaigns.

the less I earn on adsense, the less I spend on adwords.