[unclebucknasty]

You nailed it actually. Yeah, you can delve deeper, but the bottom line is one of basic supply and demand.

As the world continues to output more (i.e. increased production), the same Bitcoin will be competing for more goods (or, it can be said that more goods are competing for the same Bitcoin).

So Bitcoin's value can be said to increase accordingly. In other words, deflation.

Now, whether this is a bad thing is subject to debate. Here's an article that discusses this, specifically WRT deflation not being a bad thing with Bitcoin:

http://www.forbes.com/sites/jonmatonis/2012/12/23/fear-not-d...