This is the scenario: on one page I do have both AdSense and BURST!. When BURST! is not able to serve an ad, a web page I set up can be called. On this "default campaign" I put some text links and some suggestions. These links and suggestions are taken randomly out of a pool I created.
Soon after I started testing this, EPC plunged. The worst ever. Ads started going slightly off-topic and finally moved to something I couldn't understand. Something I couldn't understand until when I reminded about those text links of mine. Ads where moving to those topics.
BURST! creates an IFRAME and, when unable to show ads, calls my myads.html page which, in turn, shows those text links.
What drives me mad is that on a page with a lot of content, links, and clearly identifiable, one or two links, in an IFRAME, with a few words around them can completely drive AdSense to a new (mistaken) path.
If only we could know this for sure, we might use this "feature" to drive AdSense where we would like to :-)
