i'm not sure if there are already plans for this but i was thinking that maybe when there is more work done on path finding and speeding up the game the game could morph into a sort of massive world with many player controlled fortresses.
the idea is to make like a login, possibly the one used on the forums, then use that to get to your fortress. the program you would download would only be a viewing and commanding client along with a connector program that would run in the back ground, and all the processing would be done at the server. since that is an extremely large amount of power needed i was also thinking of making a sort of processing management system where the server would send packets of information to be processed, which after doing so would then be sent back, and arranged correctly by yet another program installed on the server. sort of like the SETI program that hijacks your internet connected computer for it's processor when your not using it.
of course this is going to take money so you could set up a payment plan where you can spend money to play or donate hours of cpu time. and in the end if you decided you didn't want to play a massive dwarf fortress with a ton of real players you could just download the normal single player dwarf fortress.
requirements would be a relatively speedy computer, and and internet connection would have to be something faster than dial up.
you would not be able to pause like in a normal dwarf fortress game, however if you wanted you could put a designated pause time every hour, the ability to trade, declare war, and make alliances would have to be made, and also in game dynamics fortresses would have to be more resilient to famine, drought, disease, and depression.
another thing that would be needed is the ability to look around the entire world, i suggest a zoom out ability, instead of your entire fortress residing on the entire playable map you would stake a claim to an certain area where you would have permanent rights to build, you should probably also have the ability to claim more land off of your original fortress and have branch fortresses, that are their own entity that would trade and give taxes to your original fort. this is all proportional to your payment plan. this would also be a cool feature in the normal dwarf fortress either way. if you wanted to build on someone else's land you would need to get a building permit, in exchange for anything that the other player would want, probably continued royalties on anything produced in that area.
since there will be messaging you can talk to other people and set up trades, noob protection would be in the form of incognito building, where your protected because people don't know your there yet. also a few more designations like steal, pillage, and destroy, maybe even kidnapping would be helpful for your soldiers to carry out maybe even have a separate labor menu for soldiers and workers.
I think that if dwarf fortress does become an mmo like that then it'd be freaking awesome^4 since it's already awesome to the second power