My utility doesn't seem to offer carbon offsets, so I voted No. I probably would buy them if they were available, although I find the concept a little confusing.
One thing that does concern me about carbon offsets is that I can throw a few dollars at the utility company, then crank up the A/C rather painlessly. Maybe a more straightforward way to do it would be to increase the cost of the electricity to where it can easily fund green initiatives. The carbon offset seems like green "charity" to me.