The 2006 Word of the Year was "carbon netural" in the The New Oxford English Dictionary. But there's still a lot of debate about what it means. Many people compare the U.S. carbon offset market to the Wild West. Since there is no regulation, how do you know what you're buying?

There are several guides to carbon offsets that have been created by non-profit organizations, designed to help the average consumer (see related resources). But part of the problem is that many people are still debating what a carbon offset should be. And that's a debate that can be found in the blogosphere.

One place you can find it is on the Grist.org blog which has many bloggers writing about green issues. Forestry offset projects, which sell credits based on the fact that trees sequester– or hold carbon dioxide, have come under fire. You can read about a few of the critiques here, here and here.

Another blog, Treehugger.com, has followed the issue as well. They posted this comparison of offset providers to help their readers do their homework and this more in depth guide on the issues buyers should be aware of.

Of course, one of the earliest debates over offsets was whether offsets would act as "indulgences", distracting consumers from making concrete changes in their lifestyles to reduce their carbon footprint. Terrapass, one offset retailer, has tried to investigate this by surveying their customers. They found that the majority of them had already had green habits. Still, the virtues of offsets are a matter of personal opinion.

You may listen to the "Cashing in on Carbon" radio report online, as well as find additional links and resources.

Lauren Sommer is an Associate Media Producer for QUEST.

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