AAhHH! I just noticed that when I pause a TED Talk, the url at the top changes with that number! So it's far easier that what I posted below - just pause the talk where you want and copy the URL!
Seems that when you use certain social media plugins/extensions (I'm using MeetEdgar on Chrome), you can click to share from the bookmark button when you pause the TED video and it will give a unique time number. I just did this one: http://www.ted.com/talks/julian_treasure_how_to_speak_so_that_people_want_to_listen#t-28636
There is no clear pattern, though, as the #t-xxxxx for 10 seconds was 426018, 20 seconds was 8651, 30 seconds 18670 and the one above was at 40 seconds.
I'm guessing the player creates a random number for that specific point. Probably so that people don't share just bits, but the whole thing.
I'm only guessing that some of the Twitter, Facebook or G+ plugins/extensions might do the same. Give it a shot!
~Bon