Constellation.Sitecore.Seo (nuget): This library supports a number of regularly-requested SEO features, implemented in Sitecore. Some of these have been implemented elsewhere, this approach 		is stronger for multi-site, multi-language installations. 		 		Features Included:  		Browser-based language detection and setting of the context language with the ability to generalize from a specific dialect to a fallback master 		for a given language (ex: fr-CA will fall back to fr) 		Multi-site 404 page subsystem that returns an actual 404 response code. 		Automatic Robots.txt support - configurable for each Sitecore server in your installation. 		Automatic Sitemap.xml support - fully multi-site capable; can be configured to support a wide array of information architectures. 		Rule-based approach to ensuring that Sitecore Items get the most url-friendly name possible. 		Site definition extension allowing for dynamic, site-based hostname resolution for static assets such as javsacript and CSS files.
Keywords: Sitecore