A landing page is a special page created for the express purpose of "converting" website visitors - to get those visitors to take some action such as filling out a lead form or subscribing to a newsletter. If, for instance, you were running an ad campaign to generate leads online, you would point the ad to your landing page, rather than to your home page where the visitor might get lost or frustrated.
Let's start with the subject… They used the horribly generic "Newsletter" in their subject. What most people don't realize is the easiest way to fail at email marketing is to use generic, non-descriptive subjects in their emails. A subject must be compelling, brief, and indicate the content of the message. This fails at all three and it doesn't even indicate a brand. This will be passed up in most users' inbox.
Just a reminder for those searching for niche-related content and inspiration for such content - Google has very deep tools available to help. Google Alerts and Blog Search are fantastic, as are the Books searches, just as examples to get you fired up!