This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
Also note that for code like that, if the threads are sharing the same instance, then if you don't use proper synchronization, you may get undesirable results. For example, you could have 100 threads executing, and the count could end up at 1, or at 2, or at anything up to and including 100.
subject: Is it possible to execute the code by multiple thread simulataneously?