To tell you what Blog Action Day is all about, I quote from the offical web site:
On October 15th, bloggers around the web will unite to put a single important issue on everyone’s mind - the environment. Every blogger will post about the environment in their own way and relating to their own topic.
So, it's about the environment, baby. As a user and promoter of Linux, especially Ubuntu, I'd like to share with you some thoughts about how environmentally friendly Linux is and/or could be. Let's start by pointing at the incredible amount of discarded electronics often containing dangerous toxic waste. No matter what brand of computers, our aim must be greener computers and entertainment electronics.
Power consumption increases with each new generation of desktop computers. Oftentimes, older hardware can still be used for fileserver or router work; a number of Linux distros are small, yet advanced enough to run on old machines. Thus, we need to produce less new hardware, which is also a power-consuming process. If you want to reduce power consumption of your high end Linux desktop system, you can try to install PowerTOP, a tool to measure power usage developed by Intel. Also check out all the tipps and tricks at LessWatts.org, a site dedicated to saving power with Linux.
Having said this, it is kinda sad that the next Ubuntu release Gutsy Gibbon that is due on October 18 will consume more energy than any of the older releases, despite the fact that it comes with a tickless kernel.
Conclusion: There is still a long way to go, but at least hardware as well as software developers are increasingly aware of the problem; and many are working to resolve it.