What's google web master tools for and how does it compare to google analytics

Does anybody know what google web master tools offer I have google analytics on and I just realized I could register for google web master tools. not s开发者_StackOverflow社区ure if it's worth. any feedback would be welcome

Google webmaster tools is more about your site and how google looks at it with its search engine. You can configure things like crawl access, rate and view your sites loading speed and possible crawl errors.

And analytics as you know is about your visitors.