In theory, massively multiplayer gaming isn't a genre. It's everything else - a business model (or several), a technological framework, a social philosophy. There's little to dictate that MMOs have to fit a particular style of design or gameplay.
In practice, of course, things have been very different. There are a number of reasons why the massively multiplayer online role-playing game has come to totally dominate the field. Online gaming's roots in the early multi-user dungeons, or MUDs, is one of the most important, along with the RPG form's relatively lax requirements when it comes to lag. But these reasons become less relevant with every passing year, while the need for MMOs to diversify - as well as the need for other spheres of gaming to access the gushing revenue streams of online gaming - becomes more intense.
Yet it still hasn't quite happened. The overpopulated wilds of free-to-play gaming have seen all manner of gaudy and variously misshapen hybrids spring up in the bid for attention, but few have risen above the general hubbub. In the MMO mainstream, space sim EVE Online is just about the only departure from straight fantasy role-playing to achieve longevity and distinction. Realtime's crime actioner APB has recently made a bold stab for new ground, but Planetside is barely more than a memory now, and the MMO shooter still remains a mystifying, distant holy grail.
Taking real-time strategy gaming into the massively multiplayer realm has long been one of the more talked-about cross-breeding projects in the gaming geneticists' labs. There are challenges - not least the fact that each player needs to be represented by multiple units rather than a single avatar - but there's also a natural synergy with a genre that has long been synonymous with online multiplayer and the PC platform.
End of Nations could well be the first credible stab at the MMORTS. It's being made by Petroglyph, an RTS specialist formed by former Westwood (Command & Conquer) developers, the men behind Star Wars: Empire at War and Universe at War. The publisher is more of an unknown quantity: Trion Worlds, a well-funded MMO specialist banking on nifty server technology and the traditional subscription business model to make its mark. It also has internal studios working on fantasy MMORPG Rift: Planes of Telara and an ambitious project with the Syfy TV channel whereby players' actions in an MMO will affect the plot of an accompanying TV series.
When we saw Rift (then called Heroes of Telara) at E3 last year, it's fair to say that its unique features grabbed our attention ahead of its generic art and setting. Much the same was true when we saw End of Nations at E3 2010.