Originally Posted by mcc235

Facebook will read the meta tags of a post and use that as a description. On Gary's blog post, in the source code, is:

<meta property="og:description" content="Frequent flyer expert Gary Leff shows you the trick to Qantas First Class award availability -- how to get the toughest awards in the world, there's a secret to it!" />

So it's taken directly from there. The other post has the first part of the post as the og:description, which is generally how it works by default. It was not changed like the Qantas post.