Does Culture Jamming actually do anything?

I got onto this topic because observing global reaction to to our new pesident has me chomping at the bit to do something socially active using my time or money. I haven't found anything yet that I can really embrace. There are a number of truly worthwile global causes that I could give my own money/time to, but I want to do something with serious leverage. How can I turn one hour of my time into 1000 man hours to actually due some good, or to make 1000 people think for a few moments and decide to do something good on their own. So I thought about becoming a "culture jammer", engaging in subvertising with other socially conscious types trying to get people to consider the global implications of of corporate and governement actions, and hey, it's kind of cool.

The problem is I have no idea of its impact, has anyone who has seen a subvertisement actually changed the way they behave, purchase, or even think about these issues. Or is it just another way to be part of a group of the (socially conscious) indie urban elite. Does the truth.com ad campaign cause people to smoke less, to invest less money in cigarettes? There are all kinds of little cool groups doing things like putting up fake ads and throwing little awareness events, but do these actually do anything or are they like a berkeley protest, just minorly increasing the noise of the signal. So, I remain eager to do something, but without an outlet. I suppose I will just end up giving a reasonable sum to a worthwile charity where most of the money actually goes to the projects rather than being pissed away on overhead ( I recommend Child Vikaas this charity actually runs very leanly with 100% of the donations actualy funding projects, not administration)