I've long time invisioned the idea of an online pokemon game. Maybe it would be like this...
1. Trainers: You could fight preset trainers like in the games, or you can fight online trainers, in the field, or anywhere, for that matter.
2. Doubles battles: You can team up with your friends to take on opponents online.
3. Evolving storyline: The story could be updated daily, and the trainers of the online world could change the story just through their actions. Also, this evolving story could result in new regions being discovered.
4. Houses and rooms: Might be tough, but taking the "Clubhouse" idea from Ruby/ Sapphire, people could customize their homes, and such.
5. More interactive tournaments: Using the people from around the world playing pokemon, you can do many games. Imagine the bug catching contest with people from around the world!
6. Gyms: Maybe, people can take control of gyms, if they become strong enough.
7. Good vs Evil: You can play as Team magma, Aqua, Rocket, or the good guys. This results in daily story changes.
8. Weather: The weather for online games could greatly affect the way certain events play out.
9. Need for multiple trainers to beat specific areas: Exactly what it says here.
10. Jobs: You can get a job, as multiple things, run a pokemart, be a nurse, be a professor, police, Mayor, President, Exec, ect...
11. Chat: Talk to the people from around the world while on the field or in battle. Also, could receive and write mail via mailbox, or on your computer in the game, to recieve in game e-mail, or just mail in your mailbox.
12. Trade pokemon and items.
13. Listen to the radio of real world or pokemon world
14. New areas to be discovered. In frequent updates, new areas can be added to the game.
15. Start in Kanto, Johto, Hoenn, Orre, or another region as you make your way with people from around the world in the pokemon universe.
16. Real world Calender: Real world events can affect what happens in the game. EX: Halloween is halloween in the game.
17. Real world clock: Self explainatory.
18. Exclusive pokemon on certain holidays. (Maybe)
19. The addition of new pokemon to the game and an automatic update to your version of the game every time you go online.: With the update every time you go online in the pokemon universe, all stated earlier could be updated to your game, such as new regions and events, as well as, possibly, the addition of new pokemon.
20. I can keep going on, but I think you all get the jist of this. Would most likely take a dedicated team of game designers, graphics designers, ect to do it.
To sum this all up, an online pokemon game would be revolutionary, and the possibilities are endless. If someone was to do it, they should be commended around the pokemon, and gaming world.