I experienced that Wordpress itself is constructed in a way which gives you an advantage towards average sites regarding the page rank because it is google-optimized by nature. (e.g. because of the clean separation of content and layout) So you only need to optimize it with different tools when you have a lot of time and really need to be on top. There are some things which are to avoid, like using to much tags or create duplicate content.
Take the first entry for example. Google can find the same content on 4 different pages:
http://cassiopaea-cult.com/category/laura-knight-jadczyk/
http://cassiopaea-cult.com/category/cassiopaea/
http://cassiopaea-cult.com/category/cointelpro/
http://cassiopaea-cult.com/2010/10/22/is-cassiopaea-a-cult-and-is-laura-knight-jadczyk-a-psychopath/
There are different plugins available to avoid this, so that google only crawls the real blog entry (not categories, tags, archives, ...) and, therefore, they don't evaluate it as duplicate content what leads to a better listing.
The Google page rank is mainly about how many other websites with similar content link to your site and how good their page rank is, not about continuous updates. But of course, if you have more subpages (blog entries) you will have more readers, there is more to link on to and there are more key words with which your blog can be found.