Carbon Offsets - Effective or Not?

On today's front page of the Washington Post is an article titled Cost of Saving the Climate Meets Real-World Hurdles, about carbon offsets and their actual effect. It says that because it is an unregulated market, not all produce the results that people pay for, so industry standards might be put in place. And while one guy quoted says he feels it's okay to keep his gas-guzzling vehicle since he paid for offsets, the Sierra Club advises remaking your life to become eco-friendly before spending money on offsets.