Usually content as in your layout, say for instance whether you user WordPress or blogger or another blog platform, your static pages and your blog posts will be the freshest content. The search engines will gobble those new updates.
That is why they have those pay to blog sites as it really is fuel, like 'word of mouth' for businesses and other sites.
The blogroll is a nice place to give a site you like extra special attention and would not have to be searched into so deeply. It is right there. However, it will only be crawled any time you update your layout or your blogroll, so it is not as effective as being mentioned within a blog post.