Valve have sent through word they'll be celebrating four years of success with Team Fortress 2 and the first full year of user-generated, and sold, content through the TF2 Mann Co. Store, with a significant update they're calling the "Manniversary".

The Manniversary Update includes several new features, including Steam Workshop, an improved item submission system that allows community item-creators to test, share and track the status of their creations. The entire TF2 community will also be allowed to participate by browsing, rating and offering feedback on all submitted items. The Steam Workshop will be fully integrated with the Steam community.

In addition to the Workshop, the Manniversary Update will also ship 30 new hats and cosmetic items, an item decal system, weeklong "try before you buy" item tryouts, loadout presets, multiple miscellaneous items slots, improved game performance, and a new taunt. The Update is one of the largest and most ambitious in TF2's four-year history.

Valve has also initiated a sale in the Mann Co. Store that will run until October 17th.

"The 'Mann Co. Store' represents an important new direction for games and game makers," said Gabe Newell, co-founder and president of Valve VIA PRESS RELEASE. "By leveraging and extending the platform features of Steam, Team Fortress 2 has enabled a viable marketplace for independent content creators and significantly extended the gameplay experience in an incredibly short amount of time."

If you've ever created and sold something through the Mann Co. Store, drop a line about your experience in the Comments section.