Every 210,000 blocks that get mined in the bitcoin system, the inflation rate gets cut in half. The first time this event will ever happened, just happened. Bitcoins are now going to be a little more scarce than they were for the last 4 years. As the clock of life ticks, and new blocks are generated, the inflation rate gets closer to zero until it actually turns into the world’s first TRULY deflationary currency and the number of units in circulation will forever decrease.
Today was, indeed, a big day for Bitcoin.