I could kick the butts of every misinformed motor-mouth who creates the impression that plugins and money can put your site on the first page of Google search results.
A blog is a post based website designed for interactive communication. Post based structures wherein content is frequently updated are attractive to search engines.
A website is a page based site designed to operate as a one way means of communication ie. a noticeboard. Page based structures wherein content is static and rarely updated are NOT attractive to search engines.
blog = site with post based structure being continually updated - attractive to search engines
website = site with page based structure - rarely updated - unattractive to search engines
Any WordPress blog can be restructured from being post based to being page based, but let's put that aside for the moment. Understand that what attracts search engines is unique content the cannot be found anywhere else on the internet and that content is found in POST based structures. For greater clarity read > http://onecoolsitebloggingtips.com/2010/05/12/better-blogging-at-wordpress-com-pages-and-posts/