Google Webmaster Central is a free online tool that allows you to examine the inner workings of the relationship between your website and Google, the world's most popular search engine. Using Webmaster Central, you can help Google crawl the pages of your website more quickly, find your placement on search result pages and troubleshoot some types of problems.
A sitemap is an XML file with links to all of the pages hosted on a website. You can provide the URL of your website's sitemap to Google through Webmaster Central. After you do this, Google's Web crawling robot will download the sitemap and look for changes each time it crawls your website for new content. This may help new content that you add to your website get indexed by Google more quickly.
The "Crawl Errors" of Google Webmaster Central are generated when Google's robot crawls your website. This can help you diagnose and fix pages that are missing, links that you typed incorrectly or a problem with your website's "robots.txt" file. Note that this section will also show crawl errors if you have intentionally used a robots.txt file to restrict Google's access to certain areas of your site.
The "Keywords" section of Google Webmaster Central displays the most common keywords that Google finds while crawling your website. Google determines the subject matter of your website by its keywords; if you look at this list and do not feel as though the keyword list presents an adequate view of your website's theme, you may need to consider making changes to your writing.
Google Webmaster Central displays the keywords and keyword phrases that result in your website being displayed on Google's search result pages. This section also shows the number of people who click through to your website after seeing it on Google. Attracting traffic to your website depends on attaining a high ranking for the keyword phrases relevant to your website's subject matter, and this section shows where you need to make improvements.
Links to Your Site
Google determines a website's authority in part by the number of other websites that link to it. A high authority ranking -- or PageRank -- can lead to higher placement for your website on Google's search result pages. This section of Google Webmster Central shows the websites Google has found that link to yours.