website-design-gorgia would be better for google. Check out google's webmaster's guidelines:

http://www.google.com/support/webmasters/bin/answer.py?answer=76329&topic=15261

Most complain about back pains and neck pains. Maybe you have to stretch every now and then to keep the blood circulating. Better still you need to consult it with a medical professional as it may be...

Is it also useless for other search engines like yahoo?

PR is not measured by back links alone as everyone here has pointed out. Silveraden has posted a good resource to get quality backlinks. I'll try them out myself.

I'm also trying it now. One nice thing about is are the thumbnails of your recently opened websites, very convenient. It's still in beta so we can expect more features in the future.