Company of Heroes: Online (CoHO) was an MMORTS developed by Relic Entertainment, published by THQ. Although it was an excellent game, it was cancelled while in late development due to a variety of reasons.

CoHO took the RTS component of CoH, and added in an MMO type community and persistence. It had levelling, tech trees, a store to purchase in-game items with game currency or real money, special hero units and so much more to add even more variety to your armies. This level of persitence had players constantly coming back for more, and the customization lead to an almost an unlimited amount of variety. It had an overall bigger and better feel than that of CoH 1 and 2. 

CoHO was a revolutionary game that brought previously unseen customization and persistence to an already unparalleled RTS experience. Having played the beta, please, I can say for certain that it was a shame for it never to make it out of development. Its return would attract CoH veterans and new players alike and bring new life to the CoH universe.