Because Google can't spider facebook applications, previously what I have done is to load the adverts from an iframe served off a website related to the application. This was giving me ads that were relevant to the site and therefore to the application.

However for my new application I don't really have a site that I can piggy back off.

What i'd really like to do is to basically pull out the relevant content for the application and current user and embed using an invisible div into the page serving the iframe.

I understand that technically this is cloaking, but only for very genuine reasons.

Is this going to get me in trouble with Google?