The game gives no system of gaining charisma because of all those exploration contacts you have made.(a reasonable repercussion and one way to tally or reward the meeting people part of exploration).
The first version of D&D that did so (that I know of, off of the top of my head) is 1e's rules for henchman and hireling loyalty, which directly rewards how you treat people. Alignment, perhaps, should also be considered, especially in 1e where an alignment change is so costly. 1e OA's rules for honour are another example.
See also Beyond the Crystal Cave, a 1e module where there is plenty of treasure, and lots of creatures the PCs can fight -- but in which taking the treasure and/or fighting the creatures is a uniformly (or nearly so) bad idea. Indeed, the player who thinks D&D is "all about looting and killing" will very, very likely never return from this expedition. Even if much more powerful than what the module recommends.
(EDIT: I would like to see a 4e BtCC; there is a lot of material in there that could become skill challenges in the 4e system. I wonder if it would be as fun in 4e as it was in 1e? No matter what one might think, 1e was about exploartion enough that TSR envisioned and published an adventure where combat and looting were a bad idea.....
can any other edition say the same?)
Again, take a look at the advice Gary Gygax gives players in the back of the 1e PHB. It is a lot more involved than "kill things and take their stuff". Gary highly recommends parlays, when possible.
Look at the monsters in the 1e MM. Are we really to assume that pixies, nymphs, dryads, and unicorns are included so that they may be killed and their stuff taken?
Look at the magic items in the 1e DMG, or the 2e Encylopedia Magica (excellent books!). There have been a plethora of magic items throughout the history of the game that have nothing to do with fighting or looting. They very often have to do with other goals, including (especially) having fun. Thus, a Trident of Fish Command appears in 1e, and a Lyre of Building, etc., etc., etc.
(EDIT: Look at the Dungeoneer's Survival Guide, as well as the Wilderness Survival Guide. Lots of rules about exploration, the perils of the environment, and the rewards that can be reaped without combat from the environment, such as complete mining rules in the DSG, from initial assay to turning the raw ore into valuable metal.)
This thread is, in a way, very closely tied to the "World Beyond the Dungeon" thread. There are more rules related to combat because combat, for the average player, presumably requires more rules than talking. Similarly, there is more information about dungeon and cave environments offered, but not because it is assumed that bears, pixies, and treants are going to be found deep underground -- it is rather assumed that the average player (and DM) has a better idea of what a forest is like than he does what a ruined tunnel is like.
And, just as the WBTD thread is replete with folks who will ignore (or deny the existence of) all the non-dungeon rules, wilderness monsters, and non-dungeon advice given to press home their idea that it has always been "all about the dungeon", so too is this thread replete with folks who will ignore (or deny the existence of) non-combat rules, monsters unlikely to be fought, and non-combat/looting advice to press home their idea that it has always been "all about the killing and looting".
It is hard for some people to imagine that the game was different in editions they did not play, or that it has been played differently by other people over the course of its long history. Just as it is hard for some people, looking at a particular edition's combat-enhanced focus to imagine that it can be played quite differently by others (even if the official adventures start every encounter with "Have the players place their miniatures....).
It's short sighted. It's seeing some of the trees without seeing the forest. It's some other, better, cliche that I can't think of right now.
The advice given to DMs and players has changed. This is also true, and (IMHO and IME) influences those who begin with a given edition more strongly than it does veteran players and DMs.
Even so, the game is what you make of it. This is true for all editions.
