"What is normal today that was thought impossible before?" as asked in the lecture, for our Monday 5 Sep 2011 evening class...
Quoting: 

• Online flea market: eBay
  Pay money to a stranger selling a car you have not seen. This lowly innovation opened up a new kind of higher level coordination that permitted a new kind of exchange (remote purchasing among strangers) that was impossible before. 
• Wikipedia
  The idea of an encyclopedia that anyone could change at any time. 
• We now have street and satellite maps for the entire world on our personal hand held phone devices -- for free -- and with street views for many cities. 
• Today entire sections of our economy run on software instruments created by volunteers working without pay or bosses.
• The impossibility of total open round-the-clock sharing still occurred, though everyone knew humans were innately private beings.
• YouTube is theoretically impossible. But here this impossibility is real in practice.  Millions of amateurs would produce billions of hours of video, or that anyone would watch any of it.
• Nefarious hackers use social media to identify corporate network administrators, and their personal off-time hobbies, and then spoof a gift of a cool new product from their favorite company, which when opened, takes over their computer and thence the network they are in charge of.

Cheers!Jovin