OpenGraph Tags / Facebook Like Button

Hi guys,

In designing my new Wordpress blog, I have implemented the opengraph meta tags into my site as follows (pseudo-code below):

<meta property="fb:admins" content="000000000" />
<meta property="og:site_name" content="Website Name" />
<meta property="og:image" content="<?php og_image(); ?>" /> <!-- custom function to select a thumbnail based on a post thumbnail or a generic site image -->

IF THE PAGE IS A SINGLE POST:

<meta property="og:url" content="<?php the_permalink() ?>" />
<meta property="og:title" content="<?php single_post_title(''); ?>" />
<meta property="og:description" content="<?php echo strip_tags(get_the_excerpt($post->ID)); ?>" />
<meta property="og:type" content="article" />

OTHERWISE, USE GENERIC SITE OG META TAGS:

<meta property="og:url" content="<?php echo site_url(); ?>" />
<meta property="og:title" content="Website Title" /> <!-- homepage (site) title -->
<meta property="og:description" content="Website Description" />
<meta property="og:type" content="musician" />

What I don't understand is if I need to create a facebook "app" for my website. The Facebook developers site says:

Some sites may have hundreds or even thousands of pages with Open Graph protocol meta data. To handle a site with lots of pages, you can link your pages to your Facebook Platform application. This will enable you to publish stream updates to your pages programmatically. To connect your Page to your Facebook application ID, include your application's id in the fb:app_id property on your pages.

Is this necessary for a blog? There could eventually be hundreds of pages as there may be hundreds of posts... Does it really need a facebook app though?

Many thanks,

Martin