I honestly found it extremely hard to cram all of the benefits this idea truly has into 250 words, so I will take the liberty to almost cheat a little and expand here ; )

THINK ABOUT IT: Just one other rider with you on your daily commute halves your gas expense - but Its not just about halving the expense it takes you to get to and from where you need to go every day, It gets far better. Its about astronomically lowering the amount of Co2 emissions in the air, and the amount of gasoline consumed - if even one in four drivers were to carpool instead of driving, it would lower Greenhouse gas emissions by 8.9%, 509 Million Metric Tons per year and curb gasoline demand by 17.5%, or 5,244,050 Barrels/day, and that is only if one in four used the website.

In addition, the website ideas are more thoroughly expounded upon here: http://hubpages.com/hub/A-Website-to-Change-the-World

There are MANY more problems and ideas discussed there involving the idea, and it is also explained much more in depth. I highly recommend the article for anyone mildly interested, and indeed, it is required for the idea to be understood completely and not just dismissed.
---The Author

P.S. - A detailed article including all of my research will be published shortly alongside the other article describing the site on Hubpages. : )

Since my last article was written, it came to my attention that research into just how effective such a website would be is crucial to its success, and I was even more surprised at just how powerful these numbers truly were.

According to statistics gathered by the Energy Information Administration, [ http://www.eia.doe.gov/ ] a government body that lists energy statistics from the U.S. Government, if one in four drivers used the GGEA website on a regular basis and carpooled instead of driving, it would reduce greenhouse gas emission by 9% annually (509 Million Metric Tons) and reduce oil consumption by 17.5% (5,244,050 Barrels/day). If the website were used to its full potential, in an idealistic future in which all drivers carpooled instead of driving alone and it became an integral part of society, our oil consumption would be cut by a massive 52.5% (15,732,150 Barrels/day) and greenhouse gas emissions by 26.9%. Wow.

By contrast, the effectiveness of these cuts is amazing - and it is largely believed by experts that "Unless we make it easier for Americans to choose buses, subways, and bikes over cars, there's little chance for big emissions cuts from vehicles." (National Geographic Magazine, March 2009). Consider this, however: If we changed every light bulb in every home in America to compact fluorescents, AND turned off every home computer in every home when they were not in use, we would cut their Greenhouse gas emission impact by 93.1 Million tons a year (National Geographic Magazine, March 2009). Seems like a lot... but if only one in TEN drivers used the GGEA website and carpooled instead of driving, the Greenhouse gas emission impact is 209 Million Tons a year, according to my research using Energy Information Administration Data. Again. Wow.

On top of that - Changing every light bulb in America and turning off every home computer when it is not in use is next to impossible... But one in ten drivers carpooling instead? I would be willing to bet almost every single driver in the U.S. has the opportunity to carpool if they could get connected to someone going to or by their destination. Its enough to give me chills... there is a car going to your destination tomorrow that probably passes you by... even as you read this, a vehicle has probably passed by your home, going past your next destination. Its so possible, this idea, so beautifully possible...

http://hubpages.com/hub/A-Simple--Green-Idea-No2---Research-and-Feedback

http://hubpages.com/hub/A-Website-to-Change-the-World