the people who claim they are using solar and wind power actually do not - what happens is they use the same dirty power and then purchase credits from a company who supply a power grid with wind or soloar power -
use of less power on servers is great - and every little bit helps but i agree with web space - most are using it a pure marketing ploy and hype - the other sad thing is .. i know a few hosting companies that claim are green and have this entire section on their entire data center is powered by wind blah blah -- and i know 100% it is no - since their cage is down the hall from our colo room -- sad but true