One of the benefits of contextual, online ad systems is the automation. Add Google AdSense once to your template and you're set.
Of course, without being editorialized, there is always potential for conflicting or misplaced ads... which is exactly what I encountered while reading "Blockbuster aligns with CinemaNow in an effort to stay relevant" over at BoyGeniusReport. The post was fairly objective (even if calling Blockbuster a "stumbling giant") in it's description of Blockbuster's new on-demand movie download service. The only mention of Netflix was in the final line - briefly noting that Netflix too provides downloads for accounts over $8.99.
Directly below the article is a banner for... Netflix of course! And a $4.99 account at that - which wouldn't even include the on-demand service.
Not that it much matters - but these ads are run by Advertising.com