A landing page, sometimes known as a "lead capture page" or a "lander", is a single web page that appears in response to clicking on a search engine optimized search result or an online advertisement. The landing page will usually display directed sales copy that is a logical extension of the advertisement, search result or link.
Landing pages are often linked to from social media, email campaigns or search engine marketing campaigns in order to enhance the effectiveness of the advertisements. The general goal of a landing page is to convert site visitors into sales leads. By analyzing activity generated by the linked URL, marketers can use click-through rates and Conversion rate to determine the success of an advertisement.
Questions having the landing-page regards the User Experience of landinga pages which may or may not work against the goals intended by SEO.
Reference: Wikipedia - Landing Page