bumpski - 5:13 pm on Apr 21, 2011 (gmt 0)
I think it's important for this thread to remember that we're NOT discussing a Panda casualty.
If we cross up with sites that were tagged by Panda, we may well miss something important.
...an eight year old site which has done very poorly in the SERPS the entire time I've been running it.
Perhaps we're just discussing a Panda beneficiary?
If the site was slowly crawled it might be coincidence that the rankings improved just as the ads were removed.
But page load performance certainly could be a major factor and one would have to look at the onload event time before the ads were removed.
Of course Webmaster Tools, Labs, Performance should provide some historical data of "OnLoad" times. It is possible to code your pages so the ads don't affect the "onload" time.