Excellira - 7:07 pm on Jun 10, 2009 (gmt 0)
Yes, though site-wide links may not be valued as highly but you also have the opportunity to pass blog PR to your ecommerce pages by incorporating links into the body content. If you blog about travel to Venice you could place links in the body content (or at the bottom of the post) to the Venice travel page. If in the bottom, you could suggest that the visitor check out your Venice travel packages. Be careful not to overdo this or you'll undermine the trust you are attempting to build with the blog.