As a company which has recently had issues with breaches of privacy, as well as issues over the stance on how the internet should work, as well as various YouTube issues and of course the fact that are in a prime position to completely take over our lives, Google probably have a fair bit to prove that their company is as honest and free of evil as it says it is.
Chrome for a Cause will go a fair way to doing that. Google are pledging to donate vaccinations, clean water supplies, books, etc for charity for every so many tabs that Chrome users open over the next few days, providing they're using the plug-in.
I don't really use Chrome that much, aside for try to reduce lag on Tetris Friends, but it is a nice browser. If it wasn't for the fact that I have Firefox set up how I want it, and I find it's awesomebar history search stuff generally works better for me than the one on Chrome, then I'd probably consider Chrome as a more permanent option.
I think it'd be nice if they offered this extension to Firefox and other web browsers, because I have to say that it's a pretty shameless push for people to download and try Chrome, thinly veiled under the guise of being a generous, charitable act, but I guess the bottom line is that if they give a ton of stuff to charity then the ulterior motive maybe isn't so important.
I'm unsure how I really feel about this sort of thing being successful. If giving stuff to charity turns out to be a good way to get people to try/buy/use your product, then we could see it a lot more often. Which on one hand would be so horribly uncharitable in itself, but on the other hand would result in large sums of money going to charity which wouldn't otherwise.
I'd definitely recommend people download Chrome and make the switch for the few days, because free stuff for needy people is free stuff for needy people, and it's really pretty negligible effort on our part.