bobbolger: Do you use alexa for SEO and to evaluate the traffic of other websites

Alexa is one of the leading internet statistics engines. It keeps a "top billion" chart, where every webpage on the planet has its place. Beginning with Google and Facebook, it goes all the way down to the gazillionth site no one knows about. It's a chart that gives you insight on how your business is doing through calculating the popularity of your site.

and every webmaster use it?

Yes, but you need to get a feeling about it's rankings. If Alexa is above 1 million, than it is useless. Only geeks have Alexa toolbar installed, so a flower site can have 1000 visitors per day and Alexa rank of 1 million, while webmaster site can have 100 unique visitors per day and Alexa rank of 150.000.

Yes, I do use Alexa to evaluate websites I visit, I would suggest you install the toolbar as well so Alexa can start using your data to determine sites ranks.

Yes Alexa is used for evaluating the website

i use alexa and compete.com