I'm not fond of the concept of carbon credits, either. It sounds like something that can be abused. Or, more to the point, it sounds like something that people should be doing anyway: produce as little waste as possible, be as non-destructive as possible.
Carbon credits also may not be 100% verifiable - and I don't think that there's currently a US governmental check on companies that sell these carbon credits to make sure that the money is spent for the intended purpose. How is a company to know that their purchased carbon credits did actually (for example) build a windfarm in India, or a hydroelectric dam somewhere in Asia? Even if a company says that carbon credits will be used to fund renewable energy in the company's home country...just where will the US find the land to build all the windfarms / plant all the forests from carbon credits bought by hosting companies, tech companies, and all the rest? And at what point will the building of a windfarm, the planting of a forest, the building of a hydroelectric dam, be done in such a way that either it doesn't effectively generate energy, and / or it somehow causes other damage?
On the surface, carbon credits sound like a good idea. However, both chocolate and beer are good ideas, too (well...perhaps not together). Too much of either of them, though, and you won't be very happy or healthy.
Anyone know of the Dust Bowl in 1930s middle America? It happened because thousands of families rushed to the middle American plains to farm and homestead - but neither the Us nor Canadian gov't. (who provided all the land grants and encouraged people to go settle the largely-uninhabited areas) nor the new residents had a sound grasp of safe/intellingent agricultural practices. All the prairie grass was ripped up, the land was plowed and prepped for "traditional" farming...and an entire ecosystem was shredded and thousands of hopeful families lost nearly everything they had. I envision similar problems all around the globe, as a result of "carbon credits" projects implemented too quickly, in the wrong places, or in the wrong ways.
I think that many companies will buy carbon credits (some to whitewash their public image, some because they want to be as environmentally proactive as possible), and either the money will be misspent, or other damage will be done.