Have you ever wondered if it was infinite? Like when there was no more Indev. When things came out of beta. What happens... further out?

Well, there is a place called the "Far Lands". Here is a picture:
It's means you've come 12,550,820 meters from the center of the Minecraft world to the edge of it. When you get there, your fps will significantly drop and the terrain will be messed up... HARD It is a quite mysterious place, where no lighting works and everything is... bust.

SO to answer the question, Minecraft IS NOT infinite. This is because computers can only generate so much terrain. Also, it would be really crazy to have something ACTUALLY infinite. Think about it! I'm actually not really sure what is infinite other than the universe. But the universe is supposedly expanding... Minecraft isn't. Hmm, maybe the real question is yet to be answered: "What is beyond the edge?"