Apparently, some advertisers in the UK were cancelling their adspaces on Facebook, because they were appearing next to dubious content – in this case a page of the British National Party – as I found in this post at Techcrunch.
It seems that Facebook (and probably most other social networking sites) are not able to book campaigns on specific pages (or filter out unwanted pages). But, as Techcrunch rightly writes:
It seems a little strange in 2007 that advertisers would have been naive enough to believe that a run of site style advertising campaign on a site as large as Facebook would not have resulted in advertisements appearing next to dubious content to start with.
This problem is not only Facebooks‘ problem. Any social network – may be even many of the other sites with user generated sites with run-of-site advertising – will have the same problem. These sites will need context sensitive filters to deliver the right ads to the right user generated content pages. And while this works fine for text based pages (Google is offering that already for their AdSence ad placements), I am not sure how you would do the same with images, Sound and video?