ASP.NET 4 SEO Improvements
Page.MetaKeywords and Page.MetaDescription properties
One simple recommendation to improve the search relevancy of pages is to make sure you always output relevant “keywords” and “description” <meta> tags within the <head> section of your HTML. For example:
One of the nice improvements with ASP.NET 4 Web Forms is the addition of two new properties to the Page class: MetaKeywords and MetaDescription that make programmatically setting these values within your code-behind classes much easier and cleaner.
Response.RedirectPermanent() Method
It is pretty common within web applications to move pages and other content around over time, which can lead to an accumulation of stale links in search engines.
In ASP.NET, developers have often handled requests to old URLs by using the Response.Redirect() method to programmatically forward a request to the new URL. However, what many developers don’t realize is that the Response.Redirect() method issues an HTTP 302 Found (temporary redirect) response, which results in an extra HTTP round trip when users attempt to access the old URLs. Search engines typically will not follow across multiple redirection hops – which means using a temporary redirect can negatively impact your page ranking. You can use the SEO Toolkit to identify places within a site where you might have this issue.
ASP.NET 4 introduces a new Response.RedirectPermanent(string url) helper method that can be used to perform a redirect using an HTTP 301 (moved permanently) response. This will cause search engines and other user agents that recognize permanent redirects to store and use the new URL that is associated with the content. This will enable your content to be indexed and your search engine page ranking to improve. ASP.NET 4 also introduces new Response.RedirectToRoute(string routeName) and Response.RedirectToRoutePermanent(string routeName) helper methods that can be used to redirect users using either a temporary or permanent redirect using the URL routing engine.
For more goto –> ASP.NET 4 SEO Improvements (VS 2010 and .NET 4.0 Series) – ScottGu’s Blog

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