The Technology website Ars Technica has adjusted their URL rewrite rules to end with a .ars. Traditionally, sites have taken advantage of this URL rewriting capability to completely eliminate file suffixes like .html, .php, .aspx etc, under the theory that this made for better SEO (since the content of the URL was more relevant to the content)

Ars Technicas, though, look like this:

http://arstechnica.com/science/news/2011/03/flow-from-the-poles-drive-sunspot-levels.ars

So, is Ars Technica adding the .ars file suffix purely a vanity play? Or is it an SEO trick to improve the site's SEO by cleverly inserting their site name into every URL slug?

And, if this is indeed an effective SEO trick, should other sites follow suit?