This is something interesting. Try going to http://www.circaventures.com/ You will get a venture capital company.
Now go to google and search "Circa Ventures". The first result you get is the exact same domain but the description is "medical website". Click it, you get to same domain but now a medical drug website is shown at exactly same domain!
One can of course see the previous website visited and accordingly force display of the other website but why? Is this SEO experiment? Or am I missing something? Other possible reasons?