What do you think is the total time saved on debugging, Google-searching, testing, etc. by all of the developers of the world collectively as a result of Stack Overflow providing quick, reliable answers to their issues?
From a Absolute perspective: Negatively Infinite.
The time caused by the addiction, outweighs the time saved on question searches.
From a Relative perspective: Infinite.
I've had problems solved here, that I would never have solved without the help, after days of looking all over the internet.
For the time saved searching, and the knowledge gained: priceless.
For everything else, there's a card with two circles with SO and SF colors kissing on it.
1 / ± 0
Jon Skeet can give you the precise answer.
About 1% of the time lost because of the invention of the internet :)