The character of Wisam is a reference to Arjuna in Mahabarath, more specifically the Virata Phase. This is a period in Mahabarath when the Pandavas had to spend their last year in exile in disguise. They live in a different country where they can be recognized. Arjuna takes the guise of a eunuch and teaches dance and song to the girls of the king. This is what exactly Wiz's character does as Vishwanth.
No other movie has generated much controversy in the history of Indian cinema for the past 50 years or so. Initially bogged down by DTH release, later by ban; Vishwaroopam should be the only movie to have multiple releases (a belated release in its native state). The movie first had a Worldwide release on January 25, 2013, then in North India (Hindi) on February 1, 2013 and followed by Tamilnadu on February 7, 2013. This hampered its collections very badly. Mr. Chandrahassan reported that the delay in release resulted in a loss of around 40-60 crores for Raj Kamal International. An interesting fact is that even though DVD's were freely available in the market prior to its release in Tamilnadu, people were unwilling to watch the movie in DVD's and preferred to watch the movie only at theaters. This clearly shows the respect that people have for Kamal Haasan.
This is the first Indian film to be mixed in Auro 3D, a 11.1 surround sound format.
The Nigerian is shown shaving his hair before preparing for the bomb explosion. This is common practice observed by terrorists of a certain faith, believing that they'll be clean while entering the heaven.
In TV news shown when Obama talks about Taliban's momentum being broken, the news flash below says "Petroleum prices increased by 3%", hinting at the war on oil perspective.