To help manage and administer your website both Google and Bing provide a free service to help their search engines understand your website. You can submit your sitemap, set your preferred canonical domain (www vs. non-www), set your geographic targets, get notified of crawling errors and a variety of similar tasks a webmaster would want to perform or know about.
To access this information, you need to login into Google's and Bing's Webmaster Tools and add your site. Both services will require that you verify you own the site your trying to manage. This is can be accomplished by adding a specific file to your site, setting up a domain record or adding a HTML <meta> tag to your page header. With Semiologic's Script Manager the latter is easily accomplished. You simply go to Settings in your WordPress Dashboard, select Scripts & Meta, enter the <meta name=……. /> line provider by the Webmaster Tools, save and then verify. That's all there is to it. Easy and painless site verification.
(Note: Google does provide a couple of additional verification methods using your Google Analytics code or Google's Tag Manager)