Mustrum_Ridcully
Legend
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EDIT: To make it more clear: one in a web like model could manage his resources to gain some leverage from diplomacy to gain a better position in combat -if he has such a resource and wants to resort to that resource: to what resource one resorts has to do with his position on the web. And here is where the game takes place (it is a game where positioning matters so I would call it a game of strategic positioning )
Don't you think this system might be a little too ... abstract?
I would say you can implement parts of this in 4E, combining skill challenges and Quests and encounter design. Your in-game resource is not described by a position on the web, but basically by XP.
For example, if the PCs run a succesful skill challenge with a potential ally, they get XP for that challenge -at the same time, this XP is deducted from the XP from an encounter where they use this ally as an asset. He is using his own power to divert some of the enemy forces from combat, or he is directly accompanying the PCs to aid them, or he is giving them advice how to avoid some enemy troops.
And the other way around, a combat might help the PCs to satisfy a quest ("Get back my daughter out of the Kobold Lair") to gain the new ally (or the opportunity for a skill challenge to make this man even more thankful than just giving you some GP and a magical trinket).
Your "web" approach is interesting, and seeing an actual implementation might be even more so. But I am still not convinced that it "works" to facilitate a good role-playing game experience, and doesn't just introduce the general problem of mechanics for non-combat - replacing verbal interactions between players and DMs with dice rolls.