they patched the Duplication Glitch.

Go to the TTG home page and there is an article about iit and it tells you all the stuff that was blocked/patched.

The main ones were:
Fixed Duplication Glitch
Fix Frame Rate Lag
Fix leaderboard crashes etc

Ok thanks guys <3

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Features:
Added an autosave, and the ability to turn autosave off, or set it from 15 minutes up to 2 hours in 15 minute steps.
Split the sensitivity controls into an in-game sensitivity and an in-menu sensitivity.
Added an Interface Opacity slider in the settings for plasma screen users.
Added a gamertag display in splitscreen, and the ability to enable/disable it in the settings.
Added an option in the settings menu to enable/disable in-game hints.
Added an option in the settings menu to enable/disable tooltips.
Added a co-ordinate display to the in-game map.
Added new sections in the How To Play on Multiplayer, Sharing Screenshots, and What's New.
Added a warning message when attempting to place lava near the spawn area.

Fixes:
Fix for the leaderboard crash when toggling between filters/leaderboards.
Fix for server disconnect message appearing when offline or in leaderboards.
Fix for issue where posting a screenshot to Facebook caused a back out to the main menu.
Fix for clay generation.
Fix for 'Awaiting Approval' showing all the time on some signs.
Various crafting menu fixes.
Fix for being able to stand on sugarcane.
Fix for intermittent crash on saving.
Fix for duplication bug with the furnace and dispenser.
Fix for not being able to place water near the spawn area.
Fix for intermittent problem on entering the Nether putting the player above the Nether world.
Fix for frame-rate drop around the edge of the world.
Fix for intermittent problem where some achievements were not being awarded.
Fix for graphical issue with stairs.
Fix for issue with enemies spawning inside a house when they shouldn't.
Fix for Zombie Pigmen not being counted for leaderboard scores.

These were listed in the home page of the TTG post about Minecraft