So, what the hell am I talking about? Let me give you a concrete example, and a personal wish list of mine for many a long year.
When I was growing up, one of the most capturing games was Championship Manager. This allowed the player to experience running a club, from transfers, tactics, training and more. However, the thing it always missed was being able to actually play the game. In terms of actually playing the game, when I was younger, the FIFA/EA Sports combo was hard to beat, although now I prefer the Konami Pro Evolution Soccer range.
I've always though that it'd be amazing to merge these two together, and I think now with Web2.0/Mashups/Cloud Computing and Web APIs this really should be possible. I could easily see a situation where as a gamer I could mash two of these together. For the tactical, and running of the game, I could use Championship Manager, and as a simulator for the actually games, I could use my game of choice. In this instance it really comes down to player stats. If I could load the game from Championship Manager, with the teams, players and 'stats' to boot, I could play out the game in my simulator and then upload the result along with accommodating stats into the cloud where my 'managerial' game could pick them up from, and vice versa.
Really, this is ripe for the picking.