It might seem passé, but I think the hot topic of 2012 has been mobile Internet. The ITU disclosed in June 2012 that mobile‐broadband penetration in the developing world was at 8% versus 51% in the developed world by the end of 2011. However, as Mary Meeker of KPCB reported earlier this year, India saw the number of mobile connections actually eclipse fixed desktop connections. We have had some degree of mobile data since 1997 (and CDA connectivity earlier in the 1990s, and a kind of rudimentary 1G from the 1970s), 3G only arrived as recently as 2007. But more importantly, 2012 was the year that mobile finally became not only popular, but practical. Only in 2012 did a large number of websites on the Web become optimised for mobile viewing.
Corriere della sera also requested a prediction for the hot topic of 2013. There are many possibilities, but I suspect that one hot topic for 2013 will be the stabilisation of (some) disrupted industries.
From 1996 when MP3 piracy made its debut, music, film, publishing etc. have been heavily disrupted. Each has to some extent hit a bottom, with many incumbents failing, and some adapting. Premium or local newspapers, for example, are starting to see successes with metered access. Online distribution of music and film has starting to yield some revenue. By the end of 2013 these disrupted industries should be showing signs of stabilisation, but at a far lower level than before.