Many of us in the SEO industry take a primitive look at cloaking adopting the view that page templates/design and user experience should be consistant for bots and people. However what if we where to vary that user experience based on referring URL. For example show less ads to social media visitors from Digg and Reddit, and try engaging them with more content. Take direct visitors and give them a user experience completely different than those of search engines. If you think it's "bad" ask yourself the question is what you see on Amazon the same as the person next to you ... or does it change based on who you are ...