it is so helpful, Google suggest that webmaster make link more human friendly and friendly URL attract user to click more. Keyword in URL also attract user who searching for that keyword.
another good news for sub domain ... my client site that host under me and my subdomain, rank well in google search (top three), it just 8 thousand search result but i'm happy with it cause they did nothing (no google, yahoo, msn submit, only WP sitemap n all seo plugin) ... the site age less then a month and not more then 20 post ...
Keyword as anchor text for link provides higher ranking in search engines due to more the no of inbound link and traffic.
after 4 month running this domain(www.penangusedcar.com (geo+keyword)) with wordpress and auto feed plugin, it seem like keyword domain make important role .... Backlink : 3 (stated in backlinkwatch.com). PR : 0 Index by google : 197 pages. SERP : "Penang used Car" 1-3 depend on google country search (610k to 800k) SE Traffic : daily 20 - 50, monthly 1000 visitor from SE. for me keyword domain worth the value ....
Keyword in Content URL on Content keyword in Sub URL keyword on ALT tags keyword in title tags keyword in image Name keyword in Mata tags keyword in Anchor tags
Although it is a good thing to have your keywords in URL. It is helpful in SERP, But links are also important for better SERP. If you have links from high PR sites than this will help u a great deal in improving your SERP.