QUOTE (Ancient History @ Sep 15 2008, 07:24 PM)

Seriously, though: when Shadowrun was a young little RPG, the Karma system was fairly new. Not completely original, but as opposed to D&D, where you just heap you get XP for killing monsters and finding treasure and heap it up in big piles until you reach a magical level, you get a GM-determined number of points for whatever you do which you can spend on whatever abilities you want.
To expand a little bit on this :
On one side, you have systems like D&D, where XP are an abstract ressource for character improvement and advancement is codifed by strict levels and classes.
This, in theory, furthers the development of archetypal characters and provides efficient ways of balancing various options against each other, as it minimizes possible synergy effects by restricting options, as well as giving an accurate measure for the power of a given character.
On the other, there's systems with a focus on realism such as Runequest, where you have no XP, levels or classes, but rules for improving skills and attributes through downtime training and ingame achievements (like outstanding successes that can represent a breakthrough in your application of a certain skill).
The idea behind this being that the function of character development should be to mimic how learning works in the real world.
Balancing and having a quick reference for a character's power goes out the window, but is probably also much less of a concern.
SR, and WoD as well, take a middle ground, but are actually closer to the D&D approach, as they are not bothered with connecting the type of experience with the type of improvement.
E.g., you could just have had a run that consisted mostly of legwork and sneaking around, but are free to put your karma into raising your gunnery skill, even though you never used your rocket launcher throughout the run.
We still have an abstracted character improvement ressource, but no restrictions on when to spend it (levels) or templates on the effect it has on your character (classes).
The focus of this approach, and SR in general, is not so much being more realistic than D&D (an approach that was a driving force in the development of many RPGs in the late 70s and early 80s), but increasing possibilities for character customization.
An approach that probably started with the HERO system in the mid-80s and basically came up by redeveloping the realist school of RPG design towards the heroic approach of OD&D, but with keeping the flexibility of the realist games in mind and implementing their mechanisms under a completely new premise, a personalized superhero paradigm that became more or less outspoken in SR and lingered as an underlying, officially denied characteristic in the mechanically highly similar "Storyteller"-systems.
Systems like SR and WoD simply change the packaging size of XP and leave their distribution up to the individual player.
You could as well call karma points something like XP chunks or building blocks, as this is exactly what they are, but karma may have sounded better when the game first came out.