every search engine has its crawler. It crawls the content in your website.Please make sure that your website should not contain any duplicate content or matching content found in other website.Search engine may ban your site.Optimize your website to your user and crawler friendly so that it can rank well in a search engine when any user type any keyword your website should result first..

Web crawlers are mainly used to create a copy of all the visited pages for later processing by a search engine, that will index the downloaded pages to provide fast searches. Crawlers can also be used for automating maintenance tasks on a web site, such as checking links or validating HTML code.

The role of crawler is to crawl or explore you website in order to index the changes you have made in your website or blog.

Different search engines have different crawlers like Google Bot for Google, Yahoo Slurp for Yahoo and Bingbot for Bing.

thanks...

search engines crawls the website as you have updated the content in blogging sites or article. make a fan page put some appealing in your wall.